You can use the grooves on your Hiker/Hiker Pro handle shaft to help unscrew the filter cartridge. To remove the handle, pull off the c-shaped clip that holds the handle in place. Once the c-clip is off, you can pull the handle shaft out of the body of the water filter. Use the deepest, middle groove on the handle shaft; put it over the “crosshairs” of the top of the Hiker/Hiker Pro filter cartridge. Grasp the handle assembly while still on the crosshairs and use it to give you more torque while loosening the cartridge.