Safeware Dual Spindle Centre Case 92mm/62mm - 35mm Backset Replacement Safeware Dual Spindle Centre Case 92mm/62mm / 35mm Backset Dual follower operation. Key Measurements & Information Backset: 35mm PZ Centres: 92mm/62mm (distance from centre of spindle to centre of key) Follower / Spindle: Dual Centre Case: Latch & Hook Non-Handed (will fit left or right handed doors)