Specifications Hole Diameter : 19mm (3/4") Total length : 56mm (2.2") Drill depth: 4mm Shank diameter: 7.8mm ( 7/32") Quantity: Total 2 Pcs Operation method Since the hole opener does not have a drill in the center, first incline the hole opener by 45 degrees during the operation, slow down the speed of the electric drill, and then slowly touch the glass stone. (Rotate and cut faster) Open a crescent socket on one side of the hole (the crescent socket plays a role in positioning), and the electric drill starts to work correctly. Do not drill too fast during the drilling process, you need to continue to add water to cool the hole opener Note Light shooting and different displays may cause the color of the items in the picture to be slightly different from the real object. Due to manual measurement, please allow error of 1-3 mm. Excellent & Sincere Service Jamiikury wants our customers to be happy and satisfied. We are passionate about what we do and proud of the products we offer.If you have any questions or concerns, please don’t hesitate to contact us. We will reply within 24 hours!