Filzer Fixie Tool The Filzer tool is the perfect carry along tool for anybody using bolt on wheels. The material is 3mm thick chrome vanadium tool steel, laser cut for accuracy. It's a little thicker than some, with the advantage being (besides the fact that it's indestructible) that it won't damage the finish on the axle nuts when you tighten to the torque needed on the drive side of the rear wheel. Also, the size is perfect for a jersey or pants pocket, with just enough length (5") to tighten the axle nuts securely. On the other end is the obligatory remover for crimped metal closures used on various glass bottled beverages.