Depending on intended use or preferred price, grips are normally made of firm or soft plastic, foam, gel, or occasionally leather. To suit the shape of a human hand better, they can be clearly smooth and round or molded.
There are two fundamental methods of connecting bike grips to a series of handlebars: pressure or lock rings. Friction grips are easily slipped onto the bars (or, more commonly, forced) and are held in place through friction between the grip inside and the handlebar.