Carry Dun Specification: 1) The device is built with a low center of gravity and equipped with a long rubber crawlers, assuring the rider a comfortable and safe ride. 2) Regardless of the carried weight, the speed is automatically controlled, allowing the caretaker to operate the device easily. 3) Release the control handle to stop the vehicle, even on stairs. 4) The exclusive rubber crawlers will not damage the stairs made of any type of material. 5) A winning product of the 9th Meritorious Invention Award 6) No need to install tracks on stairs.