Stealth ViperLiner or Shader Both Stroke 3. 5mm Color Blue, Red, & Grey Machine Type Cartridge Rotary Machine Motor Info and Max RPM Faulhaber Coreless Motor & 12000RPM. These coreless motors also feature an extremely low rotor inertia and zero cogging or preferred rotor position, as well as a uniquely high, power to volume ratio. Universal Clamp Can be used with Standard & Twistlock Grips. Twistlock grip is not included. Brand Stealth (Viper Cartridge Series)