International O-ring Sizes

An O-ring, or toroidal seal, is the most common type of seal used in the world today.
Used to form a physical barrier to prevent the mixing of gases or liquid fluids, the simple toroidal shape of an O-ring has proven to offer high sealing efficiency across a wide range of applications.

Perlast perfluoroelastomer (FFKM) O-rings can be manufactured to any of the following international
O-ring standard sizes:-

• SAE AS568 American Standard O-ring sizes
• British Standard BS1806 O-ring sizes (imperial)
• British Standard BS4518 O-ring sizes (metric)
• British Standard extended series 500-800 O-ring sizes (imperial)
• ISO3601 International Organisation for Standardisation O-ring sizes (General purpose)
• ISO3601 International Organisation for Standardisation O-ring sizes (Aerospace)
• German Standard DIN3771 O-ring sizes
• Le Joint Françias 'R' O-ring sizes
• Japanese Standard JIS B 2401 (P, G and V) O-ring sizes