A medical device may comprise a sheath configured to be inserted into a body lumen of a patient. A distal end of the sheath may include an elevator for changing an orientation of a medical device. A handle may include an actuator. The actuator may be operably connected to the elevator. Activation of the actuator may cause movement of the elevator. An engaging portion may, in at least one configuration of the handle, protrude from a surface of a handle body toward the actuator. A force exerted by the user on at least one of the actuator or the engaging portion may cause the handle to transition between (a) a first configuration in which the engaging portion interacts with the actuator to inhibit movement of the actuator relative to the engaging portion and (b) a second configuration in which the actuator is movable relative to the engaging portion.