Nuke Flex Fuel Sensor Adapter - Full Flow Nuke Performance Full Flow Flex Fuel Sensor Adapter. Bypass design lets you use an ethanol content sensor without flow loss. With the Nuke Performance bypass Full Flow Flex Fuel Sensor Adapter, you can mount your ethanol content sensor on both the pressure and return fuel line in your fuel system. Delivered without the sensor.  Fits most common GM flex-fuel sensors  Bypass design exceeds AN-10 fuel line capacity  AN-10 ORB inlet/outlet for maximum fuel flow  Work on both pressure and return fuel line  Lightweight design, with an integrated bracket  4 x Viton O-rings for long durability When running alcoholic fuels such as E85, an ethanol content sensor is used to measure the fuel at all times to gain accuracy and performance from the ECU. The most commonly used sensors have a very small flow capacity which doesn´t fit a high performing fuel setup, but with this sensor adapter, you can put the sensor on both the pressure and return side with clo