Kapton / TopOwl
There is no Kapton in the MRH 90. A couple of other nations also specified this mod for their NH 90.
I don't know how heavy the TopOwl is, but any extra weight over a standard helmet would be to project flight symbology or FLIR images on the visor. I'm not sure if the IIT are removed for day flight. For NVG ops, which is bread and butter for troop lift missions, the placing of the IIT on TopOwl is supposed to give better weight distribution than having the tubes located in front of the eyes. There is also no requirement for a battery pack and counterweights as used with an ANVIS setup.