The Pro 25 Traction magnets are the strongest mags you can make without going to a neo mag. Pro 25 get there name from the Level 25 days of Polymer magnet racing. These magnets can also be used int h Viper V1 and BSRT G car with magnet shims. These should be run with hard rear tires such as our PST ROCKs or Albinos. We also recommend using a stiff chassis. (The stiff G+ chassis is black)