KAMERAR COMB: SD-1 Mark II Slider Dolly Video Stabilization System + 7" Friction Arm + Phone Mount for DSLR DV Camera SmartPhone The total length of the Slider Dolly SD-1 Mark II is 24" inches, which will allow the carrier platform approximately 15" of linear slide in between both axles. The width of the axles are 7" from wheel to wheel. The wheels use high end roller bearings with smooth (roller blade type) rubber wheels. Use the 7" Friction Arm and Phone Mount to get creative positioning with your phone. This listing includes: (1) Slider Dolly SD-1 with 1 Year USA Limited Warranty. (1) 7" Friction Arm. (1) Phone Mount