6901-06-04 HYDRAULIC ADAPTER 3/8" MALE BOSS SWIVEL X 1/4" FEMALE PIPE SWIVEL 90 DEGREE
THREAD SIZES FOR 6901-06-04 HYDRAULIC ADAPTER 9/16"-18 MALE BOSS SWIVEL X 1/4" FEMALE PIPE SWIVEL 90 DEGREE
To measure threads, Calipers work very well.