Variants of a mold are catalogued separately, so each one has its own sets and minifigs. Check these too if something you expect is missing here.

• 25167 Launcher, Weapon Gun Blaster / Shooter / Fire Nozzle Mini with Towball Socket and Dark Bluish Gray Trigger [Complete Assembly] this part is a sub-part of it
• 15392 Launcher Trigger, Weapon Gun Trigger Pair of this part