Makeblock mBot Add-On Pack for Six-Legged Robot mBot-P01-02 98050Beetle: Instead of running on wheels, Beetle walks on its six legs (aluminum beams). Mantis: Two front legs are added to the mBot to make it become the Mantis. The front legs are mechanically connected to the back wheels so, as the wheels rotate, the legs move along. Crazy Frog: Four legs replace the original wheels to mimic a frog. Dimensions: 3. 23 x 5. 21 x 3. 24 inches Weight: ~264g