Universal fuel tap 6mm with on/off switch Universal fuel tap 6mm with practical on/off switch. We recommend this fuel tap especially for engines with modified carburetors and intake manifolds that no longer have a vacuum connection. By simply turning off the fuel tap, you can prevent fuel from escaping while you are working on your carburetor. Diameter: 6mm. technical data manual fuel tap: Diameter: 6 mm/ 6 mm With ON/OFF switch