The Whites Carburator Vacuum Gauge Set is the perfect way to tune your carburators to sync on twins, triples and four-cylinder machines. Includes both 5mm and 6mm adaptors, 5mm adaptor will fit most Honda, Kawasaki and Suzuki's with the 6mm adaptor fitting most Yamaha and European bikes. The ideal kit to keep your carburetors correctly balanced regularly and inexpensively! Improving throttle response ensuring your bike is running at optimum performance.