The SPR conversion kit lets you convert many yo-yos to use the new SPR system. The SPR system out of the box (well bag actually) can upgrade or repair any Buzz-on yo-yo to use this system. The SPR system is a way to give your yo-yo a wider gap for better string play (by making it less responsive). But wait, that's not all. With some modification these super spacers can be retrofitted into many other yo-yos. This will allow you to use a Bearing C (a large bearing) in yo-yos that normally use smaller bearings. You do this at your own risk. The following list is a list of guidelines. If anyone figures out other mods that can be done with these spacers, please e-mail us.

All Spintastics Yo-Yos and All Team losi Yo-Yos. - You need to mount in the Buzz-on nuts instead of the stock ones, and use locktite on one end of the provided bolt into one nut for it to work.
All other Yomegas: Don't use the provided nuts or axle. You will need to find or make a longer threaded axle and the spacers and bearing will fit (you have to provide this new axle, the stock ones don't fit). You may also have to sand off the starburst.

Duncan Hard Core Line (Freehand 2, Flying Panda, Throw Monkey): Don't use the provided nuts or axle. Just replace the spacers and bearing with these new spacers and bearings.
Duncan Pro-Yo's (Pro-Yo,ProFly, Dragonfly, Bumblebee): Don't use the provided nuts or axle. You will need to find a longer bolt than the yo-yo comes with, the spacers and bearings will fit over the break pads in the dragonfly or the empty axle hole for the profly. The stock ProYo bolt will almost fit, but will strip easily. (Hint: the longer bolt from the Freehand 2, Throw Monkey and the Flying Panda, works.)
Heck these things can make a KonKave bearing fit into almost anything, and they let you put friction stickers into a bee. The SPR also allows you to experiment with different response stickers with out ruining your original setup. Perfect for quick changes.

This kit comes with two SPR spacers, a pair of Diff-pads (thin) a threaded rod, a pair of nuts, and a type C bearing.