Sprocket with toothed ring gear for STIHL chainsaws A : 13 mm B : 11,5 mm C : 66 mm D : 17,8 mm Pitch: 325 Teeth: 7 Compatible with chainsaw models: 017 - 018 - 021 - 023 - 025 - MS170 - MS180 - MS210 - MS250 Article No. 370088