Addressing safety concerns on its submarine fleet, the Indian Navy is looking to procure 30 Submarine Emergency Position Indicating Radio Beacon (SEPIRB) systems along with suitable SSE sleeves. The SEPIRB is a radio signalling device used for locating a submarine in distress. It is stowed onboard a submarine inside the pressure hull. At the time of emergency, it is retrieved from storage and launched either from surface or submerged condition. The SEPIRB surfaces and transmits a digital message to the COSPAS-SARSAT satellite network, which obtains the position of the SEPIRB to within 100 yards using the onboard GPS receiver. The transmitted message contains the current elapsed time since activation, the unique EPIRB ID and initial location obtained by GPS. If no GPS location is obtained and/or transmitted by the SEPIRB, then its location (to within approximately two miles) will be determined by standard COSPAS-SARSAT methods. Six hours after activation, the SEPIRB begins to transmit a 121.5 MHz beacon which is used both in locating / retrieving the buoy and as a backup to the COSPAS-SARSAT message transmissions.