A medical device system may include a delivery device including an outer sheath and an inner shaft having a coupler fixed to a distal end of the inner shaft, and a replacement heart valve implant releasably attached to the coupler, the replacement heart valve implant including an expandable anchor member and a plurality of locking mechanisms configured to engage with the coupler. The delivery device may include a plurality of collars configured to secure the coupler to the plurality of locking mechanisms. The delivery device may include a stop element configured to selectively prevent disengagement of the plurality of collars from the plurality of locking mechanisms.