Don't Tread on Me
For parade and ceremonial purposes the Royal Brigade makes use of a blue, white and red striped scheme, the colors of the Davion family.
Per FM:Federated Suns, page 75
The Brigade's insignia is a variation on the Federated Suns' crest, with each RCT adding its own modifications. The Third Guards' insignia is a phoenix, carrying the Davion sword in its claws. Per FM:Federated Suns, pages 75 and 81.