That must be the prototype 1980s handheld o-scope
hey it works and it was free i'm not gonna complain
be sure to have it calibrated...find the oldest crappiest electronics shop, go to the back and get the greasy old guy to do it...he's been doing it forever
its all ready been calibrated by my eletronics teacher at my college. they got new ones and were tossen the old ones out. this quarter he's going to teach me how to calibrate it my self. there more stuff i'm getten this quarter. yea its old but it does its job.