The Gage Mod Courier Add-on for PAYDAY 2 has 10 achievements.
Collect 15 packages with the red spider stamp on to earn a red crate.
Collect 5 packages with the green mantis stamp on to earn a green crate.
Collect 10 packages with the yellow bull stamp to earn a yellow crate.
Collect 20 packages with the blue eagle stamp on to earn a blue crate.
Collect 25 packages with the purple snake stamp to earn a purple crate.
Earn one of each crate.
Modify the CAR-4 rifle with a Competition Foregrip, CAR Quadstacked Mag, and a Competitor's Compensator.
Modify any pistol with a Pistol Red Dot Sight and a Flash Hider.
Modify the CAR-4 rifle with a Gazelle Rail, Tactical Compensator, Compact Holosight, Wide Stock and a Military Laser Module.
Modify any AK rifle with a Lightweight Rail, AK Slavic Dragon Barrel, AK Quadstacked Mag, and a Funnel of Fun Nozzle.