If you're a fan of foamboard airplanes (like the popular Flite Test designs) you know that the usual way to mount servos into the foam is with hot glue. This works, but it's difficult and messy to remove the servos for repair or replacement or just to move them to a new plane.
Just glue these frames into your plane and you can mount your servos with the included screws. The frames provide hard points for the screws to grip and make it easy to remove the servos later.
These frames are sized for the popular HXT-900 9g servos and others with similar dimensions.
Just cut a hole in the foam board, push the frame part-way into the hole, squeeze some hot glue under the tabs and press it down flush.
You can press the frame lightly against the board to dent the paper, marking the area you need to cut.