The quality minimum is the chromolybdene steel. Handlebars must resist to twisting in fall but to don't break.
The good compromise is aluminum type 7000 handlebars. They have received a heat treatment that allows them to bend and regain their shape.
The leader in dirt bike handlebar is Neken a french factory in our city Angers ! The Renthal Twin Wall with its two layers provide even greater security.
Pitsterpro dirt bike use 22mm fixing diameter for steel and 28.6mm for 7075 aluminium