Welcome Ricky,
Tosco is an Italian company. Not part of the UFIP collective, and not rotocast (although a lot of people get both of these things wrong thinking Italian = UFIP and UFIP = always rotocast).
Robert Zildjian (yes that family, and founder of Sabian) was involved in Tosco, and at various times Tosco produced cymbals which had ink showing that relationship. Some great, some cheaper lines.
Yours is a high quality cast cymbal from B20 by the look of it. Ride cymbals in that diameter are scarce these days, but not unheard of in previous decades.
It might make a nice hi hat bottom if using it as a ride doesn't take your fancy. But be aware that it is probably metric (38 cm) and very slightly undersized in inches (14.96"). So if you try it as a bottom hat under a true 15" top the bottom will be slightly smaller. That's not a problem, just something to note.
This site has some info on Tosco if you scroll down. Some of the Italian stuff needs revision based on the information I've got, but the Tosco stuff is not too far off the mark in a way that matters other than to cymbal historians.
http://robscott.net/cymbals/italian-cymbals/
Hope this is enough to give you some idea about it. There are a few of us here who love Italian cymbals. Others may chime in if they want to add more detail. I've kept it simple for now.