Isn't it a standard tripod fitment with a standard shutter release so would fit most if not all cameras? If I am right then it might be of particular benefit to user of a 35mm camera with a big or biggish telephoto. The lens gets support from one hand under the lens and grip is pressed into the area between the shoulder and chest and fired with the other hand so effectively you can use it in a similar way to a photo-sniper camera
Just speculation on my part but if I am right then it would certainly be useful to wildlife and sports photographers with heavy tele-photos
pentaxuser