These heads look completely different from anything else on the market. There's a reason for that. Gnarly Headz are designed to be "the most advanced popper head you will ever use," with a range of features to make a more fishable fly that is easier to tie. It doesn't matter how many hits you get if the fly you are using fails to hook fish. Poppers are notorious for missed fish. Often this is due to poor head design and/or the wrong hook choice. Gnarly Headz are made to hook and hold fish when used in conjunction with a compatible hook. Use the included table to choose a hook with the correct shank length and gap (or gape) for the popper head you are tying with or to choose the recommended Grip hook. They include many features to make tying easier and more consistent. These include hook insertion markers, a rear tying marker and pocket, and cavities for the eyes. The eye cavities are made for specific eye diameters and are noted in the information below. Gnarly Headz Small Freshwater Hook - Grip 30012 Hook, #8Saltwater Hook - Grip 21711NS Hook, #2//0Minimum Shank Length - 17mmMinimum Hook Gap (or Gape) - 12mmEye Diameter - 6mm Gnarly Headz Medium Freshwater Hook - Grip 30012 Hook, #6Saltwater Hook - N/AMinimum Shank Length - 21mmMinimum Hook Gap (or Gape) - 13mmEye Diameter - 6mm Gnarly Headz Large Freshwater Hook - Grip 30012 Hook, #2Saltwater Hook - Grip 21711NS Hook, #4/0Minimum Shank Length - 23mmMinimum Hook Gap (or Gape) - 16mmEye Diameter - 8mm Gnarly Headz Extra Large Freshwater Hook - N/ASaltwater Hook - Grip 21711NS Hook, #6/0Minimum Shank Length - 29mmMinimum Hook Gap (or Gape) - 20mmEye Diameter - 9.5mm