Tag is missing, I've always assumed it was an 066 but not 100% certain. Head has 1122 on side.Runs well, compression at 150 and cylinder looks good. The item "Stihl 066 Chainsaw ms660 ms661 Running 150psi 32 Bar- See Details" is in sale since Monday, December 9, 2019. This item is in the category "Home & Garden\Yard, Garden & Outdoor Living\Outdoor Power Equipment\Chainsaws". The seller is "humboldtsales" and is located in Bend, Oregon. This item can be shipped to United States.