Spyderco TriAngle Sharpmaker Diamond Rods (Pair), 204D
[C204D]

This is a definite must if you have lots of knives that you wish to reprofile. Since I own a lot of S30V's, D2's and lots of harder Rc knives, it would usually take me a while to get the back angle on. Since I got these diamond ones, the process has been so much quicker and easier. Very handy for handtools and bits also.

Remember to push slow so you don't destroy the diamonds!