GPH1 type co-axial single tilt assembly - Prism can, prism, and holder are fully compatible with Leica/Wild prisms. 34mm offset. High precision copper coated prism HI, offset and push button on holder are compatible with Leica GPH1; parts are interchangeable also. Just because you paid a lot for your EDM/Total Station, doesn't mean you have to for your prism system. CST's "snap-in" prisms and holders are interchangeable with Leica/Wild holders and prisms. Your satisfaction is guaranteed! Prism canister dimensions, locking and functioning are identical to Leica/Wild GPR1, allowing you to replace your prisms in canisters for a fraction of Leica's cost..all this without compromising range or quality.