About Us

McMasters Koss Company provides IATF 16949 and ISO 9001:2015 registered manufacturing and stocking distribution of O-Rings, Gaskets, Custom Molded Seals and Oil Seals.

Started by industry veterans, Robert (Bob) McMasters and Martin (Marty) Koss in the Detroit Metro area in 1977 to distribute O-Rings and seals to automotive manufacturers.

McMasters Koss Founders
Shipping Department

A Dedication to excellent quality and meeting on time requirements established McMasters Koss Company as a trusted supplier to large manufacturers in North America and worldwide.

McMasters Koss supplies O-Rings and seals to a wide variety of industries and major OEM manufacturers for automotive, truck, food and beverage, petroleum and other important industries.

McMasters Koss Industries We Serve
Iso Certificate Scope

McMasters Koss Company implemented a formal quality system in 2000 and has completed our ISO 9001:2015 Quality System certification in 2016.

We have completed our 2021 surveillance review and will have a new certificate valid until February 2023.

McMasters Koss Employees are generally long term with average tenure of over 15 years. Team members know how to quickly address your needs and accomplish objectives.

McMasters Koss Team Coat
End of 2020 Calendar

McMasters Koss is classified as a essential business in 2020 and have steps in place to continue supporting our customers during the worldwide pandemic.

Please click here to review our Covid-19 Safety Measures.

With over 20 years experience supporting engineering groups across North America and worldwide, we offer full support to your production facilities.

Please reach out to us with any Sealing Solution or logistical challenge you may encounter.

McMasters Koss Global Shipping
  • McMasters Koss Bulk Parts Shipment
  • McMasters Koss Commercial O-Ring Inventory Hallway
  • Customer Specific O-Ring Inventory
  • McMasters Koss Bulk Inventory Area
  • Shipping Department
  • Pallet ready to ship
  • Durometer Tester
  • O-Ring Micro Vu Measurement
  • ASTM Specifications for O-Rings and Rubber Seals
  • McMasters Koss Global Shipping
  • McMasters Koss Headquarters Complex
  • Oil Seal Environmental Test Machine
  • Quad Rings
  • Fluorocarbon O-Rings and Seals
  • Extruded Rubber Gasket
  • Custom Molded Rubber Seals
  • O-Rings
  • McMasters Koss PPAP with APQP Manuals
  • White Rubber Balls
  • Molded Rubber Seals
  • Oil Seals
  • Custom Molded Seals
  • Extruded Rubber O-Rings