About

Specializing in extremely tiny and precise, high quality rubber products for wristwatches. Our products were used in Japan as well as Switzerland for the molding precise quality. Since then, KEF has expanded its business to areas including sealing water, gas, automobiles, HDDs, digital cameras, ink jet printers, industrial instruments, medical equipment, endoscopes seals, fuel pump diaphragms for jet engines, O-rings for aerospace astronaut suits and more. KEF conducts extensive research in order to develop the efficacy of our products to meet the highest standards in the world. This is especially true with regards to the technology of mixing fine rubber particles, of which we have outstanding expertise and have been successful in developing one of the smallest O-rings.

Established in 1967 in Chiba Japan as an O-Ring and seal supplier for Seiko watches.
Became the leading O-Ring and seal manufacturer for Swiss high brand watch makers by 1980s and expanded its business to Europe, Asia and America.

KEF Corporation has its headquarters combined with R&D, Engineering, Quality Control and Production lines in Sakura, Chiba Japan.

KEF Corporation has in total of 4 production sites; Yamagata and Chiba in Japan for high added value precision parts, Shenzhen China for mass production of precision parts and Samutprakarn Province-suburb of Bangkok, Thailand for mass production. 

Our sales offices are in Chiba Japan, Hong Kong for Southeast Asia, Los Angeles USA for Americas and Neuchatel Switzerland for Europe.

KEF Corporation works to identify the best custom rubber and sealing options for applications, from material selection and seal profiles. With our experience, we offer custom design services for sealing components. Our specialties are high precision miniature or micro-miniature custom seals and rubber products. We deliver to your satisfaction the highest quality products on time.

Custom made, Various shape Tiny Seals & Rubber Products
Flash Free at parting line,with shifted parting line.
Variety of Shapes and Sizes. High Precision High Quality and Chemical Resistance.

Micro orings (<1 mm Internal diameter) to small size, up to 8-10cm of internal diameter.

Diaphragms thickness from 0.1mm (0.004in)
Vibration Insulators

Class 100 Clean room Facility