This yoke is used for mounting the pocket transit to the Brunton Tripod, the Telescoping Jacob Staff (below) or any non-magnetic tripod or staff with a 1/4"-20 threaded attachment. It is designed to clamp securely into the slots on the sides of the transit. Availability: Usually ships the next business day. 3040$45.00 For information on our full line of geology, geophysical and GPS mapping products, please visit our ASC Scientific main Website at www.ascscientific.com