ACR Hydrostatic Release Kit for EPIRBsDescription A patented 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. Replacement Schedule 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 Easily replaceable 100% factory tested Patent Number: 7,435,148