Product review (4 stars): MoistAIR HDC411
The filters that arrive are MoistAIR HDC411 filters.  What wasn't included in the description was the size of each individual filter.  They are each 11 x 2 3/8 x 6 1/4.  I'm using them in an MoistAIR Emerson HD12110, and they seemed a little shorter (on the 11 inch length dimension)than the original filter.  The only other difference is that the original filters had 4 beads of plastic/urethane adhesive, and these only have three.  They seem to work fine, though, and what I'm amazed at is how much better these work than the dirty filters.  I'm putting much more water in the air at low speed immediately after replacing the filters.  I cleaned the original ones out each year, but after several years of use, they needed replacement.  Overall, these seem great, and replacement should really be an annual event, especially in areas with hard water.