The
cro-hook, is a special double-ended
crochet hook used to make double-sided
crochet, which is a variation of
Tunisian crochet. Because the hook has two ends, two colors of thread can be used simultaneously and freely interchanged.
Crafts using a double-ended hook are commercially marketed as Cro-hook and Crochetnit.
External links
A Cro-Hooking Tutorial