I used this amp for about 3 years - It was modified by the factory 10 meter kit, so it technically was equivalent to the SB220. It was a real workhorse and I did all the Harbach mods except the parasitic oscillation kit because it is no longer available. Great rig, I used it primarily on 80/40 CW and it loafed along at 1kw (that includes the 100W drive as this is a grounded grid linear). Care must be taken when purchasing one sight-unseen as some have been hacked apart for 11m CB operation and are real turds if you end up with one...the sellers on eBay of these items are less than honest and you need to be familiar with what a good amp should look like inside...