This is the CPR side. You can see the G10 CR's in both sides. there is a fiberglass tube in both sides as well. These act as the ejection tube on the NC side and the altimeter tube on the fincan side. Big Blue anodized aluminum nut and threads screw the two sections together. The 1 7/8 coupler acts as a guide. There are o-rings on everthing to seal it all.