This set of top quality V30 metal bond diamond router bits will allow most efficient shaping, honing and polishing with any portable routers. Grit numbers for each bit are 30/40 grit, 100 grit, 220 grit and 400 grit respectively. With both M10 and M8 bolts, they can work with portable routers such as Master, Secter, Stinger, Dia-Pro, Amigo, Oma and many other routers. Position 1 and 2 can be run at 6000 RPM and Position 3 and 4 bits can be run at 3000 RPM. High quality metal bond will allow the longest life for the bits. Similar set of bits are selling for more than $2000. Our price is $995, plus 10% discount when you check out. You pay only $895.5. That's only $224 per bit.