Specifically designed for fire and smoke doors, the BTS range of floor springs is Certifire approved. Proven & robust, units are for doors weighing up to 300 kg. Closing force options are EN 4, 5 & 6. All models have closing speed variable by valve adjustment. BTS 80 F has variable latching action, mechanical backcheck, cement box and hydraulically fully controlled closing from 175 degrees. BTS 80 EMB has variable latching action, mechanical backcheck, cement box, electro hydraulic hold-open and integral pressure compensation feature for multipoint hold-open between 75 and 175 degrees. BTS 80 FLB has an electro hydraulic, free-swing feature between 0 and 180 degrees with, in de-energised condition, closing action from 180 degrees and backcheck.