Full metal m4 with upgraded internals! I'm not sure the brand because I bought it as a boneyard, but it is SUPER sturdy and shoots really well. I rebuilt the gearbox with new gears, shims, Orings, and had a perfect air seal on the piston when I was done. Outer barrel threads are worn down. Shoots about 340fps w/.20g bbs. Lmk if you have questions. Paypal/Cashapp 300obo plus shipping.