The boot struts of your Mini are also called gas struts. They consist of a small piston that slides into a tube which is fixed to the boot of your car.
Boot struts are essential to keep the boot or even the bonnet of your car open without you holding it up. Especially as both the bonnet and boot of your car are very heavy car parts.
To find out which gas struts are compatible with your Mini, please select the model and engine type.