Red Air Screw Vent with O-ring
Quality stainless bolt machined for generic board pressure valves. No need for screwdriver - in fact use of a coin is recommended to prevent 0-Ring and plastic thread damage from over-tightening. Machined recess to protect washer from metal thread. Thread machined so excess air can escape with just a few turns.
NB* This takes a flat head screw driver or coin