Black O-rings are usually neoprene or nitrile rubber and are prone to ozone checking in air.
CRB rod stands new in the box arrived with cracked O-rings. The CRB replacement O-rings cracked almost immediately after they were installed.
Silicone O-rings are usually red or orange and are far more durable. They work better on rod stands than neoprene, EPDM, or nitrile for sure.
Look for 1/8" O-rings, 1 5/8" I.D. x 1 7/8" O.D. I ordered from McMaster-Carr.