300D/600D/900D Fly Tying Thread underbody Fly Tying Material

Specification：
300 Denier (100 yards per spool)
600 Denier (50 yards per spool)
900 Denier (approximately 20 meters per spool)

300 Denier is suitable for small hooks of size 16 or smaller.
600 Denier is suitable for large hooks ranging from size 14 to size 8.
900 Denier is suitable for large hooks of approximately size 6 to size 2.