Astro Pneumatic 7801 7pc. Sensor & Sending Unit Socket Set. The Set includes 7 pieces performing different functions. The hex allows the removal of oil pressure sending units. The Oil Pressure Sending Unit Socket allows the removal of oil pressure sending units on late 1980 and mid 1990 GM vehicles. The Heated oxygen sensor socket is designed with slot in socket which accommodates the connectors on heat oxygen sensors. The Offset Oxygen Sensor Socket is for use in tight spaces. The Oxygen Sensor Socket is designed to remove and install oxygen sensors in most domestic and many imported vehicles.