The Blue boater is a piece of members only headwear. There are no requirements for wearing this boater and they do not confer combat bonuses upon the player. To obtain a blue boater, the player can either trade with another player, buy one on the Grand Exchange, or receive one as a Level 2 Treasure Trail reward. The blue boater can be stored in the Costume room of a player-owned house.
When the graphical update came to RuneScape (the update bringing in HD), there was a glitch that made it look like it had a red ring instead of a blue. It still appeared blue in the inventory and was called a blue boater.