Feature●Basic white textured cover for a design that blends with builder finishing techniques for multi-family dwellings For use with two entrances; two-note chime for front door, separate one-note tone for second door so no guest will be missed Chime wires to a 16-volt transformer so you are assured of uninterrupted service and are never dependent upon batteries (use transformer C905, sold separately) Pushbutton sold separatelyDescription The Nutone BK105 is a builder chimes kit that comes with chime only. This unit wires to a 16volt transformer. It can be used for two entrances ndash; twonote and onenote chime for front and second door respectively. The chime features a basic white textured cover and an elegant, curved design. A pushbutton and transformer are required.