Sinn watch u200 sdr ezm 8 silicon u200 sdr diving watches were launched in 2010 and feature a smaller case than other timepieces having similar functionalities sinn diving timepieces are different from others available on the market because of the usage of submarine steel the u200 sdr is protected from magnetic influences extreme temperatures high and low pressure and water additional functionalities include captive divers bezel with minute ratcheting crown at 4 o clock mission timer