After a hard season of training and racing, your Mavic wheels will need some love. Place your wheels in a truing stand and grab the Park Tool SW-12 Mavic Spoke Wrench to keep them spinning true and tensioned. The smaller end, with seven splines and a 6. 5mm diameter, will fit Mavics R-sys wheels. On the opposite end, the six spline, 9mm wrench, will fit Mavic Fore equipped wheels (most tubeless mountain bike rims, its equivalent to the Mavic M40630 wrench). Steel construction and precise manufacturing ensure positive purchase so you won't strip soft aluminum nipples. The Park Blue vinyl-dipped handle provides comfort as you work your way around the wheel. As with all Park Tools, the Mavic Spoke Wrench features a lifetime warranty.