Get the ideal spool assortment for any flies you need to tie with the Perfect Hatch(R) Perfect Thread 6/0 18 Spool Assortment. The most commonly used thread will make the flies you need to make your fishing trip a success! Features 6/0 Thread Most common size thread 6/0 is really a 70 Denier Ideal for small flies Lays flat Extremely strong 18 spools/100 yards each