Davus Pentaloris

It looks male to me. However, at 4 cm, the female anatomy may not be very conspicuous, so I'd try again when it grows to be sure.

additional photos of this molt:

Because this is a species who tops out at only about 4"dls - you should be able to see the spermathecae at about 1.75" (or 4cm).
I'm going with male.

@VanessaS I had an unsexed one that molted twice in my care, but I didn't know the sex until he matured, because he incorporated the first molt in his cave walls.

Thank you for the responses.
After an evening of research, I have seen an incredible level of variation across species. I had no idea that the spermathecae can take many forms.

Here is an excellent collection of photos. https://www.tarantulaforum.com/threads/spermathecae-gallery.291/

Seeing as a Davus Pentaloris spermathecae is very dark and pronounced in this gallery, I am assuming this specimen is male. However @VanessaS, you are right that it isn't even half of its potential leg span of 11 - 12 cm so will check again next molt.

@Ungoliant, funny how differently tarantulas act. All of my Chilobrachys, and Poecilotheria specimens seem to like tidying up as they toss their molts out of their hides, whereas I caught a Caribena versicolor doing a weird massage on the molt with the pedipalps...