This new 45mm spacer is the perfect finish for those shooters wanting the CQR but not the weapon too close. The spacer will give you improved fit, comfort and performance. Made of the same grade high impact durable polymer as the Hera CQR Stock it will fit with a seamless integrated extension. Installation is easy; remove the two 4mm hex screws on the back of the stock, place the new spacer on, re-place the rubber pad and secure with the two 4 mm 2 ¾ hex screws that came with the extension. Just tighten slightly past hand tight and you are ready to go.