WITH OUT A DOUBT THE STHIL MS 261 PRO MODEL 51cc. 4 HORSEPOWER, WEIGHS JUST10. 3 LBS OR 10.8 NOT SURE it rocks and its so light your not burnt out at the days end, look at u tube videos I just bought a dolmar 5105 pro 51cc model but it was very very close the sthil 261 was $113$ more so I went with the dolmar {another west german saw} inmy opinion the dolmar is TUFFER but the sthil 261 is lighter. if its firewood your doing you don't need a larger and heavier saw look at u tube and watch how the 261 rips thru 20 in oak its AMAZING GOOD LUCK up here in bc Canada there a sale on sthils righ tnow