The Gentex GHSLFBB Surface Back Box is constructed of durable plastic that is ANSI/UL 464 listed for indoor applications when used with GHSLF wall mount low frequency horn/strobes.
Standard Features
ANSI/UL listed for indoor use only
Conduit and surface raceway knockouts included
Unit dimensions: 6.58" (16.71 cm) high x 5.72" (14.53 cm) wide x 1.67" (4.24 cm) deep