RST tubes are made of medical-grade silicone with an integral steel reinforcing wire providing a safe, kink-resistant airway regardless of head or neck position. Non-collapsible, integral steel reinforcing wire reduces the risk of kinking and provides structural integrity. Murphy Style 199060 - ID:6.0mm, OD:8.7mm, Length:33.0cm 199065 - ID:6.5mm, OD:9.4mm, Length:33.0cm 199070 - ID:7.0mm, OD:10.0mm, Length:33.0cm 199075 - ID:7.5mm, OD:10.4mm, Length:33.0cm 199080 - ID:8.0mm, OD:11.0mm, Length:33.0cm 199085 - ID:8.5mm, OD:11.8mm, Length:33.0cm 199090 - ID:9.0mm, OD:12.9mm, Length:34.0cm Notes: A standard 15 mm ISO connector is supplied with each tube. Packaged: 1 Each per Box.