A communicuff looks like an oversized watch, but instead of showing the time, the face displays a printed message. They are used throughout District 13. It is considered a great privilege to be given a communicuff, as they are given to those who are important to the cause of the rebellion. Gale Hawthorne was granted a communicuff for his help in the rescue of the citizens of District 12. Although it was later taken away because he didn't follow the rules of District 13. He eventually got it back as a bribe not to tell Katniss Everdeen about Peeta Mellark.
Katniss finds his communicuff repelling in some moments when she is furious with District 13's governing. She finds herself questioning Gale, thinking he'll just go and report everything to President Alma Coin with the communicuff in sight.
In Mockingjay (book), Gale is given a communicuff due to his bravery and for rescuing about 815 District 12 citizens. He later loses that privilege after kicking Commander Boggs in the face and breaking his nose. It seems that communicuffs are given to leaders and taken away from those who don't deserve it or break the rules.