The iridium case & rare egg was part of a special offer which is no longer in action on the server.
When no offers are on booster packs contain:
3 Blueprint Cases, 1 Special Weapons Case, 50,000 Gems, $1 million RP Cash, +5 Inventory Weight, +5 Bank Weight.
Full information about booster packs can be found
here
Offers such as the one which ran this weekend will be announced on the forums! Thankyou for supporting the community buy purchasing the booster packs.