would guess its either the tokyo marui or cyma, i have had the cyma one (which is a copy of the tm i believe) and tbh i wouldnt bother
pros- cheap to buy/run, less tempremental about the weather conditions than gas, lighter, mags are smaller so you can carry quite a few easily, quieter
cons- slow trigger response, range wasnt that good, and tbh it was not as fun as a gas blowback pistol.
my opinion save your cash and get a gbb you will get more enjoyment