TRIPOD - The launcher's tube can hold three shells.
Add an additional rocket to the rocket launcher magazine
In Destiny, TRIPOD is a Weapon Upgrade that can be found on uncommon, rare and legendary Rocket Launchers in the game. Weapons in Destiny pull each Upgrade at random from specific pools (with a few Weapons that are an exception).
To see more info on exactly which Weapons this Upgrade can be found upon click the link below:
To see more about how this Weapon Upgrade fits into these pools, please click the links below:
ROCKET LAUNCHER WEAPON UPGRADES