The XENO Modular Cheek Risers work with any of the second generation M-LOK stock and brace extensions from A3 Industries. The riser mounts via traditional M-LOK mounting hardware and can attach anywhere along the length of the extension with up to 4" of adjustment, depending on the length of the extension used. In addition to the standard adjustment via the M-LOK slots, the mount is offset, providing the user an additionali 1" of adjustment simply by flipping the mount from one side to the next. This allows the rest to extend beyond the mount if necessary, leaving other slots available for other accessories.