Height: 250mm Length: 660x504mm Body: Engineering plastics Petal: Abs-100 Wheel size: 90mm-85a Caster: Diecasting(duralumin) Brake: Rubber Color: Red(basic) Function: Inverse brake system contrary to the regular brake system, this inverse brake system makes rolleage stop automatically when the load would be free. So as soon as you get it off, it stops by return. Inverse brake operation principle this brake senses the loads on rolleagle mutually working with leaf spring and coiled spring and make the rolleagle control "go and stop". They also have the shock-absorbing function which can help you feel much softer riding. Elastic body This allows you to move the body gravity smoothly from left to right preventing you from falling down when you walk with firm, heavy footsteps on the traction plates. The harmoney of "elastic function of the springs and seesaw principle of the drive shafts" enables you to repeat the step movements steadily and speed up easily too. Caster this caster that transforms the walking power into the driving power and restores the wheels in the original positions, helps you feel the speed & Thrill and makes you trun smoothly too.