There are two main o-ring sizing types. Standard was developed for use in the USA, while the international community uses metric for their o-ring dimensions.
O-Ring Groove Design Metric • Seal & Design, Inc
uxcell Silicone O-Ring, 28mm OD, 22mm ID, 3mm Width, VMQ Seal
O-Ring Groove Design Guides Engineering Quick Reference
O-rings designing
O-Rings Sizes I.D. ( Standard / Custom Size Charts )-CNL SEALS
Seal & Design Manufacturer & Distributor of Custom Sealing Products
Oil Seals • Seal & Design, Inc • Manufacturer and Distributor
Seal & Design Manufacturer & Distributor of Custom Sealing Products
Danco O-Ring Sizes Chart
Sterling Seal & Supply - O-Ring: 2-1/2″ ID x 2-11/16″ OD, 3/32
O-RING SIZE CHART - Hercules for o-rings, hydraulic seals, cylinders
O-Ring Groove Design Global O-Ring and Seal
O-Ring Static Face Seal Groove Design Guide
O-Ring Size Chart
O-Rings Sizes I.D. ( Standard / Custom Size Charts )-CNL SEALS