This is a bulkhead fitting to conver a cooler to a mash tun. Bulkhead Fitting includes, 1/2 full coupler, 1 FDA food Grade Silicone 400 Degree o-ring 1/2 x 1 1/2 nipple, nut and washer. Use for either a Thermometer or Ball Valve. Either use the coupler on the inside for Ball valves or the outside for threading in a themometer. Requires a 7/8" drill bit to install. 1/2" FPT for thermometer connection and 1/2" MPT for ball valve connection. Also comes with spare o-ring