Rex LF Blue Block Glider -2...-8°C - The new LF Blue is a low-fluorine version of HF21 blue, the best gliding wax with a high fluorine content on the market. Slightly softer compared to the HF version. The Blue LF is used by Rex's maintenance and product development team and is the benchmark against which everything is compared. In competition use, a ski lubricated with blue LF is a good “base lubricated ski” on which HF and fluorine powder can be applied depending on the weather.