BC90 is the newest version of the IMO standard in underwater acoustic locating beacons 
 BC90   will   provide   a   minimum   of  90   days  of uninterrupted operation once activated, complying 
with  minimum  standard  specification  SAE8045A, IEC61996-1 & IEC-61996-2 & BSH approved 
BC90  can  be  used  to  replace  1:1  the  existing beacons in the field: Dukane DKM502/90, NetWave 
PT-9 

Specifications:

   Working Frequency: 37.5KHz ± 1 KHz 
   Working Depth: water surface to 6096 meters below 
   Pulse Length ＞ 9 milliseconds 
   Pulse Repetitive Rate ＞ 0.9pulse/s 
   Working Life ＞ 90 days 
   Battery Life : 3years 
   Working Temperature: -2℃ -- +38℃