This is to extend the battery base. Looks like HK trifecta has a design flaw, where it is really hard to strap a battery because only the front part of the battery touches the bottom of the tri and the second half hangs in the air. With strap being at the edge of the base.

this will make the strap appear in the middle of the mounting base.

Print with 5% infil to make it as light as possible. Attach with thin double-sided duck tape.

Attach velcro on the outside to extend the battery gripping surface.

Because 5% of infil is virtually hollow..make sure you print with plenty of cooling and slow speeds over the overhangs.

Run setup without LS filter by plugging VTX directly to battery balance plug. Saves weight and gives you clear video signal. Do it on most of my FPV birds.

Good luck.