A 1-inch diameter ball arm is the standard in underwater photography lighting rigging. Today, almost all manufacturers adhere to this standard and it makes life that little bit easier for underwater photographers. As long as your strobe, video light, torch, monitor or any other possible add-on has a 1" ball mount you know it will work. You can build almost anything from the 1" ball system. Just mix and match as many ball clamps and joints as you need. Mike's Dive Cameras mainly sells 1" ball arms from Nauticam, Inon SUPE and Deepshots. They are all compatible with each other.