Innerloc Grapid GlassMax Arrow 5/16 in.. A control stud that extends out of the back of the tip engages the barbs selecting a shooting position or a new barb extracted mode. All you need to do to switch between modes is loosen or tighten the tip. Grapid's patent pending design allows for the tip to be removed and barbs fold forward for an alternate method of fish removal. An anti-vibration sleeve inside of the tip keeps the tip secure during the toughest days on the water. The Glass Max arrow is a premium grade arrow suitable for all fish. 5/16" diameter. Package Contents: Innerloc Grapid GlassMax Arrow Innerloc 88560: Grapid GlassMax Arrow 5/16 in.