Grade 13 Double Ball Bearing Hinge.c/w M5x31mm screws It has a CE mark and is Certifire tested. Double Ball bearing hinges have always been very popular for their smooth operation, durability, long lasting design and ability to carry heavier loads than washered hinges. Recommended fitting for self closing fire doors. Fitting 3 hinges per door is recommended. It will look aesthetically pleasing and from a practical viewpoint it helps spread the load evenly and will help to overcome twisting or warping. CE marked. Comes with a 10 year mechanical guarantee and is Fire door rated. Suitable for domestic use.