Easton 5mm HIT CollarThe Easton 5mm HIT Collar (Match Grade HIT Collar) is a precision engineered hardened stainless steel component that reinforces the front end of 5mm (. 204" ID) shafts using Easton's HIT (Hidden Insert Technology) system. Protects the insert area from high impact hits, stone damage, or repeated target penetration. Available in six sizes (#0. 5 to #5) to match various 5mm Easton arrow spines. Adds 1522 grains (depending on size) to fine tune front of