If they're the 'Fatter Agnus' variety, they were around quit a lot a few years back between the A3000 and A500+. OCS owners would hack away at their 500s for 1mb of CHIP ram. It also enabled NTSC machines to boot in PAL.
They are getting increasingly rare. Its the reason why got myself a 600 instead of a 500, I didn't want to have to look for one of these.
