BMX
Sport that consists of performing freestyle acrobatics using a small, one-speed bicycle.
glove 
Leather item that reduces vibration and protects the hand against impact.
helmet 
Hard piece of equipment designed to protect the head.
handlebars 
Grips with a system of rings that pivot around an axle; this enables the handlebars to turn 360°.
single sprocket 
Wheel with teeth that is connected to the chain wheel by a chain enabling the wheel to turn; the bicycle has only one sprocket as there is only one gear.
single chain wheel 
Wheel with teeth that is connected to the sprocket by a chain enabling the wheel to turn; the wheel has only one chain wheel as there is only one gear.