Nano Silk 50D 12/0 Copper is regarded as the tying thread of choice of professional fly tyers worldwide and is the best GSP thread on the market! Being so super strong and available in such a variety of colors and deniers it has endless possibilities and can be used for micro flies to large flies.Specifications and Features: Product Family Nano 50D Length in Meters 50 Denier 50D Aught 12/0 Actual Spool Length M 50m Actual Spool Length Yds 54 yds Breaking Strain Kg 1.9kg Breaking Strain Imperial 4.2lb Product Delivery Package Spool Vendor-Color Copper Qty-Carton 12 Category Nano 50D Size-Desc Spool