Hipa Felling Dog/Bumper Spike (Inner/Outer) with Mounting Bolts Screws for STHIL 044 064 065 066 MS440 MS640 MS650 S660 Chainsaw (5 Point);

Replace manufacturer part number: 1122 664 0500, 1122 664 0505
Once you fit a set on, you will wonder how you went without them so long.