A hat is an accessory that players wear on their head. It is possible to wear one to three hats in every category at the same time.
Before accessories were introduced in 2016, every accessory was considered as a hat. Because some accessories need to be attached to different parts of Robloxian bodies, this caused problems with animations.
Triple Hat Feature
Before the implementation of wearing multiple hats, users were able to find glitches that allowed them to wear multiple hats. They were respectively called a Double Hat Glitch (DHG), Triple Hat Glitch (THG), etc. based on how many hats were being worn by a user. The Triple Hat Feature, implemented on June 8, 2010, was added as a way for users to wear up to three hats without needing to use a user-made program. In 2016, hats were changed to accessories, which allowed users to wear up to eight accessories.