This is a really nice gel foam mattress pad with channels.  I bought this for my daughters bed to try to make her bed feel like our memory foam bed so that she might be willing to sleep in her own room.  4 inches is VERY deep so make sure you get a ruler out to see how high your bed will become.  The pad had a smell once I took the plastic off but when I went in this morning I did not smell anything.  I put the waterproof mattress cover (which is the plastic type) so I don’t really sink down into it but I can feel the channels.  I think I might flip it over to the flat side because I don’t like the feel of the channels.  It’s very soft to the bare touch and delightfully squishy. 

The pad was packaged in a small box and vacuum wrapped so it was very easy to get to the bed, unwrap and unfold.  The instructions were easy to follow and everything was smooth.  Make sure you buy extra deep sheets when you buy this if you have a standard mattress.  We ordered the queen and it fits perfectly.