HydroFix Hydrostatic Release Unit for Category I EPIRBA rod system does not rely on a battery, blade or pyrotechnic device to release the beacon. This advantage allows for a quick, seamless and reliable release in an emergency. Note that this is a date-stamped product and must be replaced every 2 years from the date of installation or 4 years from the date of manufacture.Features:. Allows release of a beacon from a Category I bracket when submerged in water between 4.9' - 13.1' (1.5 - 4 m). Easily replaceable. 100% factory tested. Fits: Open Face, 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: 3.3oz (93.6 g). *Not for use with the following outdated EPIRBS: 2754,2756,2758, and 2759This product may not be returned to the original point of purchase. Please contact the manufacturer directly with any issues or concerns.