Underwriters' laboratories listed in the US (UL), Canada (CUL), for use with standard steel pipe sizes 3/4 in (20 mm) to 8 in (200 mm) and CPVC pipe sizes 3/4 in (20 mm) to 4 in (100 mm)
Factory mutual approved for sizes 3/4 in (20 mm) to 8 in (200 mm)