This CRL Sliding Door Lock requires a 5/16" (8 mm) diameter hole, making it easy-to-install without notching the glass. Lock is secured by two screws from the back side of the 'H' Bar. Available in black and satin chrome finishes, keyed alike or random. Blank Keys are available to make duplicate keys. For blank replacement keys cut on one side order Cat. No. BKEY; for blank replacement keys cut on two sides order Cat. No. B2KEY.