A lock for positioning a first medical device with respect to a second medical device includes a spacer for preventing advancement of the first medical device towards the second medical device. The spacer is movable between a lock position and an unlock position. In the lock position, the spacer is moved transverse to the longitudinal axis with respect to the unlock position. The lock further includes a rotary stop integral with the spacer for fixing the rotational position of the first medical device with respect to the second medical device. The lock further includes a clip integral with the spacer and removably securable to the first medical device in a first position to secure the spacer in the unlock position, and removably securable to the first medical device in a second position to secure the spacer in the lock position.