You'll be able to glue shards on your hat, each shard will have a unique effect to it.
Repel- Prevent wild encounters and NPC trainers from aggroing at a random chance (100%-.2% per Proc). Coincides with the Blue shard.
EXP+- Increase party EXP gain by +300% (-1%/Battle). Coincides with the Yellow shard.
IV+- Wild encounters have a minimum of (31-UsageCount) IVs on (6-UsageCount) different stats. Coincides with the Green shard.
EV+- On death, wild encounters will now provide (Base EV)*(9-UsageCount) EVs to all active party members. Coincides with the Red shard.
All hats' traits are subject to durability and will wear down depending on usage.