A surgical access device comprising: a seal assembly including an upper housing portion having a first seal and a lower housing portion including a second seal, the upper housing portion being rotatably connectable to the lower housing portion; a rotation prevention mechanism including a first component and a second component, the first component including a finger integrally formed with a circumferential edge of a main housing that is fixedly connected to the lower housing portion, the finger including a ramp located on its upper surface, the finger configured for resilient movement relative the main housing about its point of attachment thereto such that at least a portion of the finger is movable distally relative to the main housing, the second component including a protrusion that is integrally formed with a circumferential edge of the upper housing portion, the protrusion including a distal-extending member, wherein the rotation prevention mechanism is configured to prevent inadvertent relative rotation of, and disconnection of, the upper housing portion and the lower housing portion, the rotation prevention mechanism further configured to be selectively actuated by a user, such that, when actuated, the upper housing portion is selectively rotatable relative to, and disconnectable from, the lower housing portion, wherein as the upper housing portion of the seal assembly is rotated in a first direction, the distal-extending member of the protrusion travelsup the sloping surface of the ramp and exerts a force on the finger sufficientto cause the finger to move distally relative to the main housing, and when the distal extending member of the protrusion reaches the end of the sloping surface of the ramp, the force exerted on the ramp by the distal-extending member is removed, and the finger, by virtue of its resilience, is allowed to move proximally to a position in which the distal-extending member of the protrusion is distal relative to the uppermost point of the ramp, thereby preventing the upper housing portion from rotating in a second direction opposite to the first direction. a seal assembly including an upper housing portion having a first seal and a lower housing portion including a second seal, the upper housing portion being rotatably connectable to the lower housing portion; a rotation prevention mechanism including a first component and a second component, the first component including a finger integrally formed with a circumferential edge of a main housing that is fixedly connected to the lower housing portion, the finger including a ramp located on its upper surface, the finger configured for resilient movement relative the main housing about its point of attachment thereto such that at least a portion of the finger is movable distally relative to the main housing, the second component including a protrusion that is integrally formed with a circumferential edge of the upper housing portion, the protrusion including a distal-extending member, wherein the rotation prevention mechanism is configured to prevent inadvertent relative rotation of, and disconnection of, the upper housing portion and the lower housing portion, the rotation prevention mechanism further configured to be selectively actuated by a user, such that, when actuated, the upper housing portion is selectively rotatable relative to, and disconnectable from, the lower housing portion, wherein as the upper housing portion of the seal assembly is rotated in a first direction, the distal-extending member of the protrusion travelsup the sloping surface of the ramp and exerts a force on the finger sufficientto cause the finger to move distally relative to the main housing, and when the distal extending member of the protrusion reaches the end of the sloping surface of the ramp, the force exerted on the ramp by the distal-extending member is removed, and the finger, by virtue of its resilience, is allowed to move proximally to a position in which the distal-extending member of the protrusion is distal relative to the uppermost point of the ramp, thereby preventing the upper housing portion from rotating in a second direction opposite to the first direction.