This is a tangent ogive nose cone for a high powered model rocket. Dimensions: Outer Diameter: 4 in Lip diameter: 4.125 in Shoulder height: 2 in Total height: 7.2 in Mass: ~85g (assuming ABS -- mass will vary)Made using SolidWorks In my opinion, the best way to do parachute retention with this nosecone is to epoxy in a long threaded rod at the tip of the nosecone and attach the retention cord to there. This allows you to slide extra weight on if your rocket has stability issues or for use on multiple rockets.