TPU battery holders for various Whoop frames and battery sizes designed by FPV Skittles. This product is designed to fit in the frame and stay secured so it is not easily dropped. You need to work them through the bottom of the frame so that the ends stick out on both sides, as seen in the pictures. Then simply push the batteries into the ends (it should be a tight fit so the TPU should be stretched) and set it in the desired position.
The 1S battery holder is designed for the Beta65Pro V3 frame and two 1S 250/260/300mah stick-style whoop batteries. The 2S battery holder is designed for Beta85X (will also work on 75X or 75Pro / 75Pro2) frame and a typical whoop size 2S 300/350/450mah battery. The adjustable version has bumps on the size to fit slightly larger 2S batteries.