Stronghold® WS75 Container Lock™. The Squire Stronghold® WS75S Container Block Lock is a high security container lock with tamper proof technology, purpose designed for extreme resistance against the threat of a sustained attack. Features and Benefits. 80mm solid hardened steel lock body 12mm hardened boron alloy steel shackles Rekeyable 6 pin tumbler lock mechanism Over 260,000 key differs Key section can be upgraded to Restricted or Protected profile offering over 530,000 key differs Anti-bump, anti-pick, highly attack resistant Highly corrosion resistant Electrophoretic black coating. Recommended for:. Containers Warehouses Perimeter gates Commercial vehicles Industrial units