Bosch Horns Speaker With Driver Unit is made from a mixture of aluminum with abs for maximum strength and occasional weight. The horn loudspeakers include a one hundred v transformer. The horn loudspeakers are provided entirely with sturdy adjustable mounting brackets, allowing the sound beam to be correctly directed. The driving force unit must be geared up into the horn waveguide. The grooves at the driving force will make it clean to healthy the driving force to the horn waveguide.