This CRL Ladder Pull Keeper only requires a single hole in the glass. It is designed to work with our Cat. No. LLP084BS Locking Ladder Pulls only when used with a glass transom. Intended for use with 3/8" to 1/2" (10 to 12 mm) tempered glass. Brushed stainless steel finish to complement our Locking Ladder Pulls. Information on Cat. No. USW10 Universal Spanner Wrench is available.