grade laser questions/help

We currently don't have any sort of laser and I think it's time to add one I think I want a duel slope just in case we ever needed it probably the most we would ever do is clean ditches build some pads and maybe do a terrace here or there ive been looking at the spectra gl622 is this a decent unit? What's the advantage of it over the gl422? Also would like to mount the receiver on a excavator or backhoe I like the idea of the lr50 or lr60 mounted on the stick what's the differences between...

grade laser questions/help

grade laser questions/help