• 4-23/32 inch O.D.
• 3-5/16 inch bolt-to-bolt
• 3 bolt pattern
• Howhit plastic cover used on 150cc engines

The primary function of the engine bay cover is not to absorb noise, nor to make the bay look good, but rather to absorb heat. The plastic does not absorb sound, rather, the 'foam' on the inner side of your bonnet is used to absorb sound.