This #10 3-hole silicone stopper is used alongside the BrewBuilt CoolStix for Carboys. The holes are for a 1/2" CoolStix, an airlock, and a thermowell.

The holes measure 0.500", 0.413", & 0.375"

Compatible with Fermonsters and our Plastic PET Carboys listed below under "You Might Also Need".