Contains stainless steel cover and 2 electrical connectors (packard and 2-T quick disconnect). Fastener on center width: 2.1". Cut Out: 3.5" L x 2.5" H, with rounded edges. Seachoice 14571 12V Hidden Horn Meets ABYC, NMMA specifications Contains stainless steel cover, mounting plate and two electrical connectors (packard and 2-T quick disconnect). Fastener on center width: 2.1". Cut Out: 3.5" L x 2.5" H, with rounded edges. 110 db at one meter.