DS-2DE2A404IW-DE3/W(S6) is an improved version of DS-2DE2A404IW-DE3/W
Read much more about it - and everything else - on the product page for the new version: DS-2DE2A404IW-DE3/W(S6)
We have kept the product page for DS-2DE2A404IW-DE3/W so that you always have easy access to the documentation.