A Trainer hat is an accessory that can be worn by a player. It is accessible by any player who has linked a Pixelmon forum account and a Minecraft account together.
The Trainer hat can be worn by using the "/redeem trainerhat" command. To take off the Trainer hat, the "/redeem toggle hat" command can be used. "/redeem toggle hat" can also be used to re-equip the Trainer hat again if you took it off. If the player has just linked accounts, "/redeem" (with no arguments) can be used to refresh a player's Minecraft account to gain access to Trainer hats.
Trainer hats can also be changed into different colors by using the "/redeem trainerhat <red> <green> <blue>" command, where "red", "green", and "blue", are RGB values from 0-255. For example, "/redeem trainerhat 255 255 0" will create a yellow Trainer hat.