The TG in this cards name stands for "Tech Genus", the S likely stands for "Summon" and the X1 represents one Synchro monster as "X" is used in the code of the OCG name to imply Synchro.
X1 could also mean the monster destroyed in battle, meaning your opponent would be down 1 monster.
The ammo for this weapon is Level stars, as can be seen in the lower left side of the card's artwork. This is probably because the effect revolves around Synchro Monsters. Or this may just be something like a wierd spaceship and releasing the stars.