Thoughtfully designed and engineered, the Swarovski Optik BR Balance Rail can be used to stabilize any of their spotting scopes when mounting on a tripod or other support system — including the ATX, STX, BTX, STS, and ATS models. The front of the rail has a shoe that accepts the scope's tripod mount foot, and the rear has a 2-axis adjustable rest for that holds the weight of the eyepiece-end of the spotter. A quick twist of the two adjustment knobs moves the rest forward or back, and up and down, to perfectly support the rear of the scope. For mounting on tripods, the rail is compatible with the ARCA Swiss quick release system, with a 3/8"-16 socket on the bottom and a 1/4"-20 adapter plug to fit nearly all photo, video, and field tripod heads.