Two little baby zips at the top (pillow end) of the duvet to "anchor" the inner... ties at the bottom to anchor the inner, with a (very well) hidden zip for removing the inner.
Ive always had duvets, no comforters or quilts, always duvets, but this is my first "fancy one".  I am now ruined for any of the 'meh, whatevs' attitudes of my previous duvet covers in regards to their inners.
I love it.
also, its cleaner... mainly because I no longer procrastinate washing it due to the exhaustive / unfulfilling  insertion process.