No hammer, vise, or other tool needed. Insert hose with ferrule and splicer or nut and nipple in proper hole. Offset tool approximately 1/8" from end of ferrule and squeeze. Make 1/4 turn and squeeze again.
1/2" wide to crimp 3/16" - 1/4" Hose
1/2" wide to crimp 3/16" - 1/4" Hose