his is a damn good copy of the VFC. Only noticable differences are the finish, stickers, and the font of the raised words on the box is a tad different.
The VFC finish is a bit shinier like the real thing, the Dboys is much more matte and a bit rougher.
From what I can remember I believe the Dboys stickers are a bit more true to the real thing in size and font, but their's also say Insight Technologies and the VFC says Vega Force Company.
Only other notes are that the Dboys comes in their standard plastic bag and you have to put the stickers on yourself. Also the Dboys uses a spring loaded clamp for the mounting with the screw on the right side, where the VFC uses just a screw and rail clamp with the screw on the left side. Also the fire button on the Dboys is hard plastic, where on the VFC it is rubber and actually pushes in.
Don't really know what you can put in it, as it's just for looks. Look up VFC PEQ reviews if you want to know what size of battery will go in it.