Announcement reposted from Amazon:
To offer customers consistent product quantity information across stores, we standardize the size values on search and product detail pages.
Size normalization helps customers compare products before buying, and we’ve found that listings with valid size values for quantity information are purchased more often.
Your listings show the size value a customer is familiar with based on their geographical location. Normalization rules automatically extract data from catalog attributes like unit count or unit count type, then construct the size into a standard format.
To change the size value for your product, go to Manage Inventory.
For more information, go to Size normalization FAQ.