The ZSP81 is a simple device that ensures a pair of double doors close in the correct sequence when they are fitted with door closers. It prevents the secondary leaf closing before the primary leaf. This is particularly important with fire resistant doors. This product is tested to EN 1158: 1997+A1:2002 and is CE marked. DoP No EN1158-01-A0 refers and can be found on our website.The arm is formed by a flat steel section of 4mm x 25mm folded in the form of "U" which is fixed within another "U" of flat section measuring 4mm x 20mm. The end of each arm is fitted with a white nylon roller 30mm diameter to facilitate the selection of the door leaves. The long arm is slightly bent outwards and keeps the primary leaf ajar until the secondary leaf closes causing the small arm to lift up and releasing the primary leaf. An adjustment screw on the face of the arm adjusts the degree of the tilt. A small angle plate supplied with the selector is fitted to the top of the secondary leaf to make contact with the small arm roller when the secondary leaf is closed.