For the Honda HRB215, here are the blade details; the service guys determined which blade(s) work best for each type of mowing:
For the best
bagging performance, stick with the original blades:
Upper, 72531-VE2-020
Lower, 72511-VG4-020
For best
mulching performance, use the original upper, and this lower:
Lower, 72511-BG4-K00
Notes:
* For structural strength and best cut quality, always install both blades; never install just a single blade.
* Disconnect the spark plug cap and turn the fuel valve to OFF before working on the mower.
Wear heavy gloves when working around the blades. Use a block of wood to hold the blades under the mower deck so you can loosen the blade bolts. Always use the original washers and bolts.
* A torque wrench is required to properly tighten the blade bolts; set it to 36~43 lb-ft.
Any Honda dealer can get blades for you. Most Home Depot stores stock them as well. Suggested retail price for each blade is $12.98, but actual selling price is at the sole discretion of the dealer.
Find a dealer in your area using this link:
Find a Honda Dealer