The cutout size fits a 2S battery. I hold it in place with Velcro straps. I'll post some pics tonight.I'm really liking the look of these. I have finally made the decision to ditch the GP. I was thinking if using the GP chassis plates with some clod axles, but I'm thinking this could be the way to go. How does the battery hold in place and what is the cutout size for the battery?