ERA Fortress BS 3621:2007 Deadlock. Deadbolt locked or unlocked by key from either side. Kitemarked British Standard 3621:2007.
Specifications
Faceplate: 134mm x 26mm.
...
Rebates to suit Union 2277, 2237, 2226, Willenhall M4, M5, M326 and Yale PM320 Sashlocks
Key features:
Allow a mortice lock to be used on a pair of rebated double doors or French doo...