A fixed-tension bobbin either runs too loose to build a clean thread body or snaps fine thread mid-wrap; the Rite Bobbin's click-drag adjustment lets you dial tension by hand instead, from small hooks up to larger flies. Specifications Tension Range: 1–9 oz (Standard) · 2–16 oz (Mag) Arm: solid brass Tube: small-diameter ceramic, no-wear (Standard model) Grip: removable vinyl (Standard model) Half Hitch Model: adds a tapered barrel for whip-finishing Best for: fine thread work on small hooks through large hooks, tyers who break thread often on a fixed-tension bobbin, and — for the Half Hitch model — whip-finishing without switching tools. The standard model's small-diameter ceramic tube resists wear from repeated passes of fine thread, and its removable vinyl grip holds secure across the smallest to the largest hook sizes. The mag model runs a wider 2–16 oz tension range for tyers who need more resistance than the standard model offers, and the Half Hitch model adds a tapered barrel so whip-finishing happens without setting the bobbin down for a separate tool.