3D printed in PETG black 10mm spacer. Can be used with the specs that came with the rifle. No permanent modification needed. Unscrew the 2 large Allen(hex) heads that hold the rear stock on, pull out add new spacer. Reinstall. can make custom thickness(price subject to change depending on thickness) Can combine with other SL8 parts, I also have a cheek riser for sale. 20 for part. 5 for shipping if needed. thanks!