Abstract: Some embodiments provide for an inspiratory limb for a breathing circuit that includes a first segment that comprises a first heater wire circuit and a second segment that comprises a second heater wire circuit. The inspiratory limb can include an intermediate connector that includes a connection circuit that electrically couples the first heater wire circuit to the second heater wire circuit. The inspiratory limb can be configured to operate in two modes wherein, in a first mode, electrical power passes through the first electrical connection to provide power to the first heater wire circuit without providing power to the second heater wire circuit, and in a second mode, electrical power pass through the first electrical connection to provide power to both the first heater wire circuit and the second heater wire circuit.

Abstract: A key lock tumbler cylinder is selectively removed with an extraction key that is longer than a normal operating key. The last tumbler plate in a tabular cylinder series along the cylinder key slot projects into an arcuate channel in the cylinder cavity wall of the lock body. This arcuate channel does not junction with the lock tumbler plate channel but does intersect with a second channel in the cavity wall that is angularly displaced about the cylinder axis from the tumbler plate channel. However, the second channel is more shallow than the arcuate channel to confine the tumbler cylinder within the body cavity when rotated by the operating key which does not engage the last tumbler plate key aperture. A second, tumbler cylinder extraction key that is longer than the operating key includes an edge bit at the end of the key for cooperating with the last tumbler plate key aperture.