Dual Alarm M-4112-RC-BP Combination warning light and buzzer operate simultaneously. Provides two-way warning of unsafe engine operation conditions. Can be used in conjunction with either a non-grounded switch or a self-grounded switch. 12 VDC operation. Smooth red lens, 5/8" diameter. Lens snaps out for easy bulb replacement. Includes miniature bayonet bulb #1815. Aluminum mounting bushing 11/16" diameter by 17/32" long. Heavy steel case, plated to resist corrosion. Body size: 1-7/8" long by 1" wide by 1-11/16" high. Fits panels up through 13/64" thick. Suggested wiring diagrams included with each unit.