a buddy of mine turned me on to these for cutting sheetmetal...they work great..they don't work as good on thicker metal like 1/8"..but work great on thinner stuff..they don't produce the dust storm like abrasives[metabo style]..unlike abrasives they maintain the same diameter with use...they don't walk all over the place like abrasives when your trying to make a straight cut..they don't break when you [accidently] drop it...I give em 2 thumbs up...I got mine at lowes..he got his at Fastenal...they have several diameters ..I went with the 5" for $19.95...its more than paid for itself vs. abrasives...heres a link...
https://www.lowes.com/pd/LENOX-Metal...eel/1000181275