The source says this removable back cover will be put on the international version as well, as the Verizon testers confirmed about their One Max units. It will allow you to insert a microSD card up to 64 GB, adding to the 16 GB of storage already on the device, and is a welcome departure from HTC's sealed unibodies of late...
Source: http://www.phonearena.com/news/HTC-One-Max-snapped-without-a-back-cover-release-date-is-next-week_id48039
Source: http://www.phonearena.com/news/HTC-One-Max-snapped-without-a-back-cover-release-date-is-next-week_id48039