Had my cable to be laid in the wall and was looking for an LED stair lighting. Signed up for 4 pieces of this decision, because they are made of metal, fitted to the color (concrete) stairs and of course LED. Is great, there are no resistors needed. Simply the cable located on the lamp connected to the out of the wall! Something hakelig was with me the installation ... have omitted the supplied black box, since it seemed too large. Got my holes deep in dimension 10 x10 cm and in the upper part 7, since it goes away the cable from the lamp. The lamp shape is deeper at the back like a Keil..oben as below. For terminals ranging attached to the lamp "gripper" / sheets "in the lamp in the recess to halten..an one point I hurried along with acrylic. 1 star deduction there, because the light in spite of warm white is still so bright ... but the woman gefällts anyway !!!