A DSMB is a Delayed Surface Marker Bouy that scuba divers take with them underwater with a reel or spool. When you begin to ascend or if you need to contact the surface you can attach the DSMB to your reel and inflate it so it bobs up to the surface. DSMBs are quickly becoming essential equipment around the world. When you start to ascend and begin your safety stop you send up your DSMB and hold onto it with line from your reel or spool so boats in the area know you are there to either stay away or to come pick you up. After you're reached the surface keep it inflated so you are obvious and boats can keep an eye on you but remember that not all boat users may know what an SMB means so ascend carefully.
