An end effector assembly of a tissue resecting device, comprising: a proximal hub housing ; an inner drive core at least partially disposed within the proximal hub housing; a cutting member extending distally from the proximal hub housing and engaged with the inner drive core such that rotation of the inner drive core rotates the cutting member; and a lock and release mechanism operably coupled between the inner drive core and the proximal hub housing, the lock and release mechanism transitionable between a locked condition rotationally fixing the inner drive core and the proximal hub housing relative to one another thereby rotationally locking the cutting member, and a release condition enabling relative rotation between the inner drive core and the proximal hub housing thereby enabling rotation of the cutting member, wherein the lock and release mechanism includes a first portion and a second portion rotationally fixed relative to the first portion, and wherein: in the locked condition, the first portion is rotationally fixed relative to the inner drive core and the second portion is rotationally fixed relative to the proximal hub housing, and in the release condition, the first portion is rotatable relative to the inner drive core or the second portion is rotatable relative to the proximal hub housing; characterised in that the first portion includes a first stop ring and the second portion includes a second stop ring , one of the first stop ring or the second stop ring movable relative to the other to transition the lock and release mechanism between the locked condition and the release condition. a proximal hub housing ; an inner drive core at least partially disposed within the proximal hub housing; a cutting member extending distally from the proximal hub housing and engaged with the inner drive core such that rotation of the inner drive core rotates the cutting member; and a lock and release mechanism operably coupled between the inner drive core and the proximal hub housing, the lock and release mechanism transitionable between a locked condition rotationally fixing the inner drive core and the proximal hub housing relative to one another thereby rotationally locking the cutting member, and a release condition enabling relative rotation between the inner drive core and the proximal hub housing thereby enabling rotation of the cutting member, wherein the lock and release mechanism includes a first portion and a second portion rotationally fixed relative to the first portion, and wherein: in the locked condition, the first portion is rotationally fixed relative to the inner drive core and the second portion is rotationally fixed relative to the proximal hub housing, and in the release condition, the first portion is rotatable relative to the inner drive core or the second portion is rotatable relative to the proximal hub housing; characterised in that the first portion includes a first stop ring and the second portion includes a second stop ring , one of the first stop ring or the second stop ring movable relative to the other to transition the lock and release mechanism between the locked condition and the release condition. in the locked condition, the first portion is rotationally fixed relative to the inner drive core and the second portion is rotationally fixed relative to the proximal hub housing, and in the release condition, the first portion is rotatable relative to the inner drive core or the second portion is rotatable relative to the proximal hub housing; characterised in that the first portion includes a first stop ring and the second portion includes a second stop ring , one of the first stop ring or the second stop ring movable relative to the other to transition the lock and release mechanism between the locked condition and the release condition. <EOS>