Great price for the Handsome Jack Collection. Probably the best price since the sales everywhere before the BL3 release.
The key will work on Windows - it just shows Mac because the publisher Aspyr only has the rights to sell keys for Mac. But once redeemed on Steam you can download any version.
Note: This does not include the Lilith Sanctuary DLC which must be bought separately if you want it.
Thanks to Ruff Specialist for pointing the deal out.
From the website:
Shoot and loot as you explore the mayhem-filled world of Pandora in Borderlands 2 and the lunar madness of Borderlands: The Pre-Sequel in Borderlands: The Handsome Collection. Experience the award-winning FPS-RPG series, including its bazillions of guns, trademark cooperative gameplay, and all bonus add-on content.
Borderlands: The Handsome Collection includes:
The critically acclaimed BORDERLANDS 2 and BORDERLANDS: THE PRE-SEQUEL games in one package;
All bonus add-on content for both games, adding hundreds of hours of gameplay at an incredible value*
Cooperative gameplay for up to four players online;
NOTE: Includes all available downloadable content for Borderlands 2 and Borderlands: The Pre-Sequel as of December 31st, 2017.