Part suffix for Citizen Finedevice HXN49 series

I was looking at two Citizen parts and I can’t find the difference between HCM49-12.000MABJ-UT and HCM4912000000ABJT . Can you help?

Welcome to the forum.

The Citizen data sheet has the part number breakdown on page 2.

It does not show a HCM49-12.000MABJ-UT variation and the Digi-Key product search for each of the numbers shows the HCM4912000000ABJT part result for both numbers.
https://www.digikey.com/short/8jd34qp7