This saved me a bunch of money on having my reel mower sharpened at a hardware store or golf course here in town.  They wanted at least $75, and I had to call a half-dozen places to even get that!  For $20 I got this kit which not only let me do it myself pretty easily (does take awhile, and the directions are moderately involved) but also gave me a tip on balancing the screws on my reel mower properly, which I found out they weren't.  I loved the hint about tearing a thin strip of newspaper and dangling it in the blades on BOTH sides of the mower, to see if they slice it right up cleanly.  If it doesn't even come close, it may not be the blades that need sharpening, it may be that the blade itself needs to be adjusted closer to the cutting surface!  All in all a brilliant do-it-yourself product that I'm glad I bought.