A medical device comprising: a sheath configured to be inserted into a body lumen of a patient, wherein a distal end of the sheath includes an elevator for changing an orientation of a medical tool; and a handle (10, 110) having a handle body (12, 112), wherein the handle includes: an actuator (20, 120), wherein the actuator is operably connected to the elevator, wherein activation of the actuator causes movement of the elevator, and wherein the actuator is configured to be contacted by a user; and an engaging portion which, in at least one configuration of the handle, protrudes from a surface of the handle body toward the actuator; wherein a force exerted by the user on at least one of the actuator or the engaging portion causes 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, wherein the actuator includes a protrusion extending radially inward toward a surface of the handle body, wherein the engaging portion includes a hook, characterised in that the hook includes a first portion that protrudes radially outward from the handle body in at least the first configuration of the handle, and a second portion that protrudes radially outward from the handle body in at least the first configuration of the handle, wherein the first portion is configured to engage with the protrusion in the first configuration of the handle, and wherein the second portion is configured to be pressed radially inward by a user in order to transition the handle from the first configuration to the second configuration. a sheath configured to be inserted into a body lumen of a patient, wherein a distal end of the sheath includes an elevator for changing an orientation of a medical tool; and a handle (10, 110) having a handle body (12, 112), wherein the handle includes: an actuator (20, 120), wherein the actuator is operably connected to the elevator, wherein activation of the actuator causes movement of the elevator, and wherein the actuator is configured to be contacted by a user; and an engaging portion which, in at least one configuration of the handle, protrudes from a surface of the handle body toward the actuator; wherein a force exerted by the user on at least one of the actuator or the engaging portion causes 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, wherein the actuator includes a protrusion extending radially inward toward a surface of the handle body, wherein the engaging portion includes a hook, characterised in that an actuator (20, 120), wherein the actuator is operably connected to the elevator, wherein activation of the actuator causes movement of the elevator, and wherein the actuator is configured to be contacted by a user; and an engaging portion which, in at least one configuration of the handle, protrudes from a surface of the handle body toward the actuator; wherein a force exerted by the user on at least one of the actuator or the engaging portion causes 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, wherein the actuator includes a protrusion extending radially inward toward a surface of the handle body, wherein the engaging portion includes a hook, characterised in that the hook includes a first portion that protrudes radially outward from the handle body in at least the first configuration of the handle, and a second portion that protrudes radially outward from the handle body in at least the first configuration of the handle, wherein the first portion is configured to engage with the protrusion in the first configuration of the handle, and wherein the second portion is configured to be pressed radially inward by a user in order to transition the handle from the first configuration to the second configuration.