Squire Stronghold Padlock & Hardened Alloy Chain Closed Shackle The Stronghold 50mm solid hardened steel padlock combines compact design with market leading product performance. Designed to resist the harshest attack these locks can also function reliably in the very worst weather conditions. Squire's G chain offers excellent security with a 10mm diameter. All covered in Squire's protective chain sleeve making them easier to handle than non covered chains.