You likely already know this, but here goes anyway........the last page of their specs list their version of the 137 box (below), which is same as the Dahua PFA137:
Note that their specs are not all that accurate. I have 4.88 for the PFA130-E but just measured it at 4.79. The PFA137 shows 4.8.
The 3949 camera shows 4.8. Based on everything I have seen it looks like it should fit. Amcrest says it is not compatible but the camera is new and probably
is not listed on their scripts as compatible yet. I was hoping someone here had actually tried it. Looks like a nice camera with 2 way audio.
Thanks