What StockCap does

StockCap is a division of Sinclair & Rush, Inc., a privately held US corporation headquartered in Arnold, Missouri, that operates as one of the world's largest manufacturers of flexible closures, plastic caps, plugs, flange covers, and masking supplies. Founded in 1950, the company serves over 20,000 customers across automotive, HVAC, cooling systems and thermal management, aerospace and defense, industrial manufacturing, and electrical/electronics verticals, with named enterprise customers including Toyota, General Electric, Siemens, Caterpillar, and Ford.

The company's core technology stack consists of five in-house manufacturing processes (vinyl dip molding, plastic injection molding, rubber compression molding, thermoforming, and extrusion) supported by over 500 proprietary material formulas, in-house plastisol compounding with material recycling, and state-of-the-art tooling fabrication. Design is supported by PTC Creo, Siemens NX, and Pro-Engineer CAD platforms, while rapid prototyping leverages 3D printers, CNC mold milling, 3D laser scanners, and 3D MicroScribe digitizing equipment. Secondary finishing operations (silkscreening, pad printing, heat stamping, decals, punching, slicing, washing, custom packaging) are performed in-house.

StockCap operates a hybrid sales-led and e-commerce go-to-market, combining a direct field sales force with regional account managers, an online storefront for stock items, distributor partnerships, and a Latin American channel partner. Revenue is generated through unit pricing for stock items (typically one-case minimum, 24-hour ship times) and quote-based multi-year contracts for custom molded production items with approximately 3-week standard lead times. Manufacturing operations span four continents across the United States (Arnold MO headquarters, Fenton MO, Portland OR), United Kingdom (Maidstone and Rochester), China (Changzhou), and Australia (Sydney and Melbourne). The company holds ISO 9001:2015 certification (since March 2004) and ISO 14001 environmental certification. The Sinclair & Rush family of companies also includes sister businesses VisiPak (clear plastic packaging), GripWorks (hand grips and foam tubing), and Indepak (precision thermoforming).

Name

StockCap

Legal name

Sinclair & Rush, Inc.

Website

https://stockcap.com

Company type

Private

Founded year

1950

Operating status

Operating

Headcount range

251–500 employees

Short description

StockCap, a division of Sinclair & Rush, Inc., is one of the world's largest manufacturers of flexible closures, plastic caps, plugs, flange covers, and masking supplies, serving over 20,000 industrial customers across automotive, HVAC, aerospace, and cooling systems verticals from manufacturing operations on four continents.

Ownership category

akta.pro rank

Product category

Industrial Protective Components and Flexible Closures

NAICS

Plastics and Rubber Products Manufacturing (326)

SIC

Miscellaneous Plastics Products (3080), Fabricated Rubber Products, Nec (3060), Plastics Products, Nec (3089)

akta.pro primary industry

Plastic Caps, Closures & Dispensing Systems Manufacturing (IMANAEAB)

akta.pro secondary industries

Closures & Dispensing for Rigid Plastic (Caps, Pumps, Sprayers, Droppers) (IMALAAAJ), Closure Components & Inserts (Orifices, Plugs, Gaskets, Balls) (IMALALAN)

Keywords

• Plastic caps plugs
• Flexible closures
• Product protection
• Masking supplies
• Custom molded components

Headquarters

HQ city

Arnold

HQ country

United States

HQ region

North America

Offices8 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Supply Chain, Personnel, Operations, Infrastructure, Technology or R&D, Marketing or Sales

Revenue model

1. Product Protection Components: Manufacture and sale of plastic caps, plugs, flange covers, and protective components for product protection applications. Products available as stock items and custom molded solutions.
2. Custom Molding Services: Design, prototyping, and production of custom molded parts using dip molding, injection molding, compression molding, thermoforming, and extrusion processes.
3. Masking Supplies: Specialized caps, plugs, tapes, and custom molded covers for painting, powder coating, plating and finishing processes.
4. Finishing and Customization Services: Secondary operations including printing, punching, slicing, washing, and custom packaging of molded products.

Pricing tiers

Go-to-market motion3 records

Distribution channels4 records

Marketing channels4 records

Core offering

StockCap manufactures and sells flexible closures and protective components, including plastic, vinyl, and rubber caps, plugs, flange covers, thread protectors, and masking supplies. Products are offered as thousands of stock sizes for immediate shipment and as custom-molded parts engineered through dip molding, injection molding, rubber compression molding, thermoforming, and extrusion, serving automotive, HVAC, aerospace and defense, cooling/thermal management, and general industrial manufacturers.

Product overview

StockCap is a division of Sinclair & Rush, Inc. offering a comprehensive portfolio of product protection solutions consisting of three core product lines (Caps & Covers, Plugs & Inserts, and Custom Molded Products) supported by three additional product categories (Thermoformed Products, Specialty Products, and Masking Supplies). The company's offerings span two main manufacturing approaches: stock/standard products available for immediate shipment in thousands of sizes across vinyl, rubber, and plastic materials, and custom molded products utilizing five manufacturing processes (dip molding, injection molding, rubber molding, thermoforming, and extrusion) plus secondary finishing operations. StockCap also operates sister companies VisiPak (clear plastic packaging tubes), GripWorks (hand grips), and Indepak (precision thermoformed trays) under the Sinclair & Rush family of companies.

Differentiator

Problem solved

Functional benefit

Products and services

• Caps & Covers

Quantifiable outcome

• Sample lab produces parts daily for quick prototyping
• +2 more outcomes

Named customers8 records

Segments6 records

Ideal customer profiles4 records

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature5 records

Partnerships

Four partnerships are on record, tiered regional and core.

• Everest Sales and SolutionsregionalChannel Partner/ Reseller/ DistributorBusiness partner providing extension of StockCap expertise for Latin American customers. Handles inquiries and sales support for Central and South America. Contact: 52 33 3123 0848 or [email protected]
• VisiPak (Sister Company)coreStrategic or Co-development PartnerPart of Sinclair & Rush family. Manufacturer of clear plastic packaging tubes, clamshell packages, blister packs, and plastic boxes. Works with StockCap on packaging tube caps and closures.
• GripWorks (Sister Company)coreStrategic or Co-development PartnerPart of Sinclair & Rush family. Largest manufacturer of custom and stock hand grips utilizing wide range of materials, finishes, sizes and colors. Extruded foam tubing for product protection.
• Indepak (Sister Company)coreStrategic or Co-development PartnerPart of Sinclair & Rush family. Specialists in design and precision thermoforming of high-quality, tight-tolerance trays, containers, clamshells and blisters.

Scale indicators6 records

Recent moves7 records

Expansion highlights6 records

Direct peers

• MOCAP: MOCAP manufactures a broad range of plastic and rubber protective products including caps, plugs, grips, and masking components, directly competing with StockCap in product protection for industrial, automotive, and electronics customers.
• Shercon: Shercon is a manufacturer of masking products, tape, and custom die-cut solutions used in painting, powder coating, and finishing, directly competing with StockCap's masking supplies line in aerospace, automotive, and industrial finishing applications.
• Caplugs: Caplugs is one of the largest direct competitors in protective plastic and rubber caps, plugs, and closures for product protection, serving similar industrial, automotive, and aerospace end markets with comparable stock and custom molded offerings.
• Protective Industries (Protective Closures Co.): Protective Industries is a direct competitor in vinyl dip molding, plastic caps, plugs, and masking products, serving overlapping automotive, hydraulic, and general industrial customer bases with similar stock and custom offerings.

Emerging players

• PolyFlex Products: PolyFlex Products produces flexible vinyl and plastic protective caps, plugs, and covers for industrial and OEM customers, serving as a smaller competitor with comparable dip molding and injection molding capabilities in product protection.
• QSPAC Industries: QSPAC Industries manufactures protective caps, plugs, and custom molded plastic components for industrial and automotive customers, offering a more focused product line that partially overlaps with StockCap's stock catalog offering.

Regional players

• Specialised PET Packaging: Specialised PET Packaging manufactures caps, closures, and dispensing components primarily for personal care and consumer markets in select regions, offering limited overlap with StockCap's protective closures business in adjacent closure categories.

Broad incumbents

• Sinclair & Rush (GripWorks): GripWorks is another Sinclair & Rush sister company manufacturing custom and stock hand grips and extruded foam tubing. It shares materials, manufacturing processes, and customer accounts with StockCap, reflecting the conglomerate's broader industrial protection focus.
• Sinclair & Rush (VisiPak): VisiPak is a sister company within the Sinclair & Rush family that produces clear plastic packaging tubes, clamshells, and blister packs. While not a direct competitor, it shares engineering, manufacturing, and customer relationships with StockCap as part of the broader product protection and packaging portfolio.
• Sinclair & Rush (Indepak): Indepak is a Sinclair & Rush sister company specializing in precision thermoforming of trays, containers, clamshells, and blisters. It overlaps with StockCap's thermoforming capabilities and serves adjacent packaging and product protection customers.

Market position

Strengths5 records

Weaknesses4 records

Competitive moat4 records

Key risks6 records

Key highlights7 records

Customer concentration

Compliance2 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles10 records

Subsidiaries3 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about StockCap