Spare o-rings can be found in the accessories section.

Product no	Thread [G1]	Stock
A06SMR-V	3/8" UNF	Available
A07SMR-V	7/16" UNF	Available
A08SMR-V	1/2" UNF	Available
A09SMR-V	9/16" UNF	Available
A10SMR-V	5/8" UNF	Available
A12SMR-V	3/4" UNF	Available
A14SMR-V	7/8" UNF	Available
A17SMR-V	1.1/16" UN	Available
A19SMR-V	1.3/16" UN	Available
A21SMR-V	1.5/16" UN	Available
A26SMR-V	1.5/8" UN	Available
A30SMR-V	1.7/8" UN	Available
A40SMR-V	2.1/2" UN	Available

Thread [G1]	1.7/8" UN
Description	SAE locking flange