RIO developed these heads as a tungsten alternative to lead core. They are supple, do not kink and sink like a stone.
T-8 (sinks at 7 inches per second) and T-11 (8 inches per second) are designed for lighter weight rods and weigh 8 grains and 11 grains per foot respectively.
T-14, weighing 14 grains per foot and sinks at 9 inches per second, is best for single-hand rods from 8 through 12 weight, and tips for double-hand rods. T-14 works especially well with Skagit lines.
The T-17 is the heaviest and fastest sinking material of them all. At 10 inches per second, it makes light work of getting depth and casting big flies. Cut these heads to the desired length and weight to meet existing fishing conditions.