In CTF you find these power ups on the map and you can only hold one at a time, once one has been picked up it stays with you till death. There is no buttons required to be used to activate it, the power up is automatic.
This power-up will regenerate your armor at 10 armor per second until full.
Beneficial in multiple ways, the Scout power-up grants the player double speed when moving and firing as well as silent footsteps and invulnerability to damage from their own weapon.
Requires the opponent to do 1.5x more damage to yourself to result in the same amount of health/armor lost.
This increases the amount of damage you can inflict on your opponent by 1.5x.