It comes in two ways. 1) Spray can, where it is an excellent primer, and 2) bottles. In bottle form, in can be used as a nice seem filler and to texture that "cast" appearance on armor. Since it's lacquer, it will bind with plastic and it doesn't shrink like some putties. Bottles come in 500, 1000, and 1200. The difference in in thickness, with 500 being the thickest. If you need to thin it, thin it with lacquer thinner. While it's a bit hard to get right now, Dragon USA is expecting a shipment from Gunze in mid-November, so most hobby shops should be back in supply soon after. There is an excellent write up on Matt Swan's website:http://www.swannysmodels.com/Surfacer.html
Regards,
Jim- Hill Country Hobby
jimC@hillcountryhobby.com