The HydroFix Hydrostatic Release Unit (HRU) is a patented rod system that allows a beacon to be quickly and reliably released from a Category I bracket when submerged in water between 1.5-4 meters (4.9-13.1 feet). This unit is designed to work with the Sea Shelter, Sea Shelter2, Sea Shelter3, and Sea Shelter4 beacon brackets.• Fits: ACR Sea Shelter, Sea Shelter2 and Sea Shelter3 brackets• Size: 2.5 x 3.4 x 2.0 (6.3 x 8.6 x 5.0 cm)• Weight: 3.3 oz (93.6 g) 2-1/2 Inch Width x 3.4 Inch Depth x 2 Inch Height USCG Approved Black | ACR Electronics ACR HydroFix Hydrostatic Release Unit