This is a self contained rail system to strap a large lipo and mount a Tarot T-2d gimbal to. It can then be balanced and centered on the bottom of any DJI Flamewheel multi rotor with four 8" zip ties. It's assembled on two 10" sections of 4 or 5mm carbon fiber rods. After the rods are in place a few 8" zips can squeeze the two rods together. I suggest supplementing this with something on the ends so nothing slides off.
Edit: I just redid my rig with 12" x 5mm (I know, right?) and the longer space allows more room to balance if you'd like to move the camera far enough forward to lose the legs from the frame. This configuration will require an extra mini block (what holds the gimbal mount) I the center.