They don’t hold the same things all the time, depending on the situation they change the content of it. Here you have a list of everything that has been on Batman’s belt (to know what is in Robin’s just change the Bat-theme for a Robin-theme). read more
Robin's Utility Belt is an epic and iconic drop in the waist costume class. Obtained from Harley Quinn in Joker's Funhouse, Weekly Award I Robin's Utility Belt is an epic and iconic drop in the waist costume class. read more
In its first appearance, Batman's utility belt "contain[ed] choking gas capsules." Two issues after the utility belt debuted, Fox also wrote the first appearance of a bat-themed weapon, when the batarang debuted in the story "Batman vs. the Vampire" in Detective Comics #31 (Sep 1939). read more