Nylon washer for co2 regulator--which way should it face?

The nylon washer that fits between my regulator and the CO2 cylinder has one groove on one side, and two grooves on the other. Can anyone tell me which way it should face? (two grooves toward regulator?) I appreciate your help!

It doesn’t really matter–at least as far as I have been able to tell. I’ve always just put the washer in without worrying about it, and as long as the regulator is properly tightened to the tank I’ve never had a leakage problem.

+1 I never really noticed before. I did go look at two of my regulators and found both had the double side toward the reg. Might just be a coincidence though.