In this guide, you will learn where to get Contamination Casing, Infectious Injection, and Cryo Coating in Warframe.
Contamination casing, cryo coating, hypothermic shell, infectious injection, ion infusion, and charged bullets can all drop as a reward for completing the Balor Fomorian event when it appears.
The Fomorian threat event only comes occasionally, but when it does appear, it will only be for a few days, and you will need to gather Omega Isotopes to craft the Fomorian disruptor run the mission. The Fomorian’s planet will vary from person to person; just check the event tab and see which planet the Fomorian is on, then run the mission once you have the Fomorian Disruptor.
All the mods have nearly the same drop chance as each other, and they don’t have ridiculously low drop chances. Your luck should be decent enough to get all the mods before the event passes.