This is the same link used on DME Racings  Hayabusa Prostreet Bike.

Prostreet Style Rear sets

These front fender lowering brackets allow you to gain more clearance between the top of your fender and the bottom of your cowling.  They work great for owners that switch over to a 120/60/17 tire, or 16" BST Wheel. Features:

• 2 adjustable positions (7/16" and 3/4" lower)
• Comes with mounting hardware
• Sold as a complete kit

Installation - Simply remove your stock fender and bolt these up to the forks.  Then bolt your fender back on.  Not sure how low to go?  We recommend taping a 10mm socket (3/8" - 1/2" dia.) to the tire and making sure the tire can spin with the fender bolted on.  If the socket hits, the tire is too close to the fender.  As the bike speeds up, the tire will grow and it can rub on the inside of the fender if its too low. *Note - It may be necessary for some front fenders to be trimmed for clearance to the radiator on lowered bikes. What do I do with the rear fender bolts?  The rear fender bolts are no longer used with the lowering brackets.  Four bolts are enough to keep the fender on with speeds up to 214 mph (track tested!)