For my battery tray, I made it lighter by cutting it up some and using industrial strength velcro to hold any battery of my choosing and not being then restricted to a certain size. Its got to be the industrial strength velcro as the sticky backing, and the hook and loop material is outstanding as far as holding power goes. I've never lost a battery, or had one come loose even in any of my bad crashes. I use this same type of velcro for my bigger heli's and those always have held the batteries in place also in a crash.

This method is also great for just plug and play... Just place the battery there in a second, and remove it just as fast. You can also control your center of gravity easy by placing it more forward or more to the rear. This battery tray is also a stock 2 year old unit. I've seen some aftermarket types out there by other manufacturers, but in fact I don't see any improvement over a modded one ? That, and if they don't list the weight of there unit, I don't buy it period.... If they can't share that info, then I don't share my cash... Simple....