The Matco ToolsExtra-Long Ratcheting Flex-Head Oxygen Sensor Wrench, No. O2SR16, is an O2 sensor wrench for 22mm sensors. It features a 16" length with a 72-tooth ratcheting flex head with flare-nut ratcheting for additional points of contact and an open end on the other side. The flex head allows technicians to avoid the exhaust and transmission obstructions a traditional ratchet and socket would face, while the ratcheting function handles stubborn or stuck hardware without slipping off.