Yes if you look at the Stihl 180-180C IPL it shows one as an option. If you look at the clutch side of a 180 cylinder it has a boss in the casting that can be faced, drilled, and tapped. I want to machine mine and install a decomp so I can give it to my Dad. He injured his shoulder and has a very difficult time starting his MS170. Once started he can run that little saw just fine. He's 80 years old and stays active keeping the trails and field perimeters cleared on his property. He has resorted to putting his bar in his bench vise so he can pull the rope with both hands to start it cold. (Yes, I argued with him about bending the bar, etc.....ever try to convince an 80 year old man that he shouldn't do something he's already done several times....doesn't work) Once warm, he can drop start it....although it hurts his shoulder, he can still start it warm. With a decomp valve, I'm betting he will find it much more enjoyable to do his work around the farm.