Innerloc 3 Blade 100gr Expandable Broadheads - 3pk - Mechanical broadhead with adjustable cutting diameter and no o-ring design. Uses spring retention clips to keep blades from opening prematurely. Cutting Diameter: 1 1/8in or 1 7/16in. Spring tension clip holds blade open or closed Stop collar lets you choose two cutting diameters (1 1/8in or 1 7/16in) No O-ring design