Slowmove door fittings come in a combo to install sliding smooth doors. It should only be used with 19 mm boards. It has an anti-derailment system using a spring in the lower car, with an anti-jump adjustable stop on the upper skate. It has an exceeding upper brake that allows opening in either of the two senses. It works for 2 and 3 doors. The lower carriage is adjustable in height more or less than 7.5 mm. It has ball cushion bearings. The pieces of this combo are plastic. Resist a weight of up to 50kg. Each packaging contains a totality of 2 units.