Sinn watch ux sdr gsg 9 ezm 2b bracelet this diving watch is made for professionals which means that it comes with numerous useful complications the case is made of german submarine steel and no wonder why this sinn timepiece is the official service watch of the german gsg9 special forces in addition the watch comes with uni directional captive divers bezel temperature stabilized chronometer long life lithium ion battery high and low temperature resistance and scratch resistant sapphir