Briton 5240.57.S.SS | Latch 57mm Backset - Square Forend (5240)
Finishes: SS Stainless Steel
Part of the trusted Briton 5200 series from Allegion, the Briton 5240.57 offers key features, including a unique X-Tension adjustment system. This allows easy customisation of spring tension to match different lever furniture weights, preventing lever droop and ensuring smooth, consistent performance. The latch is fully reversible on-site without dismantling the case. With a 57mm backset and compatibility aligned to BS 8300 guidance (57mm centres), this latch integrates seamlessly into modern door preparations. It is CE marked to EN 12209 (classification 3X810F-B020), fire-tested for up to 90 minutes on timber doors and 4 hours on steel doors (with appropriate intumescent protection), and backed by a 10-year guarantee for long-term reliability.
- Additional Product Details
Latch 57mm Backset - Square Forend.
- Latch withdrawn by lever handles
- Unique X-Tension feature allows the spring tension to be adjusted to suit the weight of lever furniture and to eliminate lever 'droop'
- Quick reversible latch without the need to dismantle the lock case
- Dual profile can be used with Euro or oval profile cylinders
- 57mm backset and 57mm centre in line with guidance of BS 8300
- 10-year guarantee
IMPORTANT - For fire door installations, the lock must include intumescent protection to maintain the door's integrity.The Briton 5200 Series is a contract-quality mortice lock case range compatible with Euro or oval-profile cylinders. The Series offers the most common range of lock functions. Performance Level 3.
Briton Fire Door Closers | Briton Exit Devices | Briton Locks
Relcross Limited (trading as) Door Hardware Online | Hambleton Avenue | DEVIZES | Wiltshire | SN10 2RT | United Kingdom | T: ++ 44 (0) 1380 720 062 | F: ++ 44 (0) 1380 729 888 | E: britonsales@doorhardware-online.co.uk
- Certification
EN 12209: 2003/AC:2005
UKCA | CE | 90 Mins Timber | 240 Mins Steel | Warranty: 10 Years (Mechanical)
Certificates, including DoPs downloadable here
- Resources | Downloads


