Built from pre-waxed Dupont B-50 Dacron. Each strand is served with an abrasive-resistance mono-filament serving. Sizes up to 44" are for compound bows that require teardrop (regular loops). Sizes 45" and up are for recurve/longbows (large loops). BOW STRING WEIGHT CHART: 12 strands for bows to 45lbs. 14 strands for bows 45 to 55lbs. 16 strands for bows 55 to 70lbs. 18 strands for bows over 70lbs.