Bulbs sold separately. Permanent traffic signal light - 890 series. Easy mounting with mounting clamps (sold separately). Mounting clamps allow mounting of up to 3 signal lights in series. Various stickers (sold separately) for marking the lens. Twin version for increased safety in case of incandescent lamp failure. Single socket: incandescent 25 W, E27; double socket: incandescent 2 x 15 W (maximum 15 W when using stickers).