Universal 4" 102 dB Steam Cleanable Single Sound Regulation Round Back-Up Alarm (92918) by Truck-Lite®. Single Sound Regulation, 102 DB, 4" Round, Steam Cleanable, Back-Up Alarm, Grommet, PL-3 12-24V. This product is made of high-quality materials to serve you for years to come. Designed using state-of-the-art technology and with customers in mind. It will meet your needs and deliver great quality at an affordable cost.