One of the best base locks on the market, fitted to all GS stringing machines for fast lock - unlock spring loaded operation.Centre lock screw is 12 mm diameter, hence very strong and durable. Will fit most stringing machines with 14 mm slot in rail, bushes available for stringing machines with 18 mm slots. The hole diameter in the base lock is 12 mm, will accept most swivel clamps with 11.95 to 11.98 mm pin diameter. Total weight 800 grams. 2022 model, manufactured with CNC machine. Made in Taiwan with 5 years guarantee.