Excellent deal for an excellent product I've been using for over 4 months. Got mine during Spotlight's 50% offer and had inspected the unit thoroughly. It doesn't come with the foldable cutlery but it's got a very big opening and 500ml. Longest I've tested for my lunch staying warm was for over 5 hours and that was done without pre-heating the container with hot/boiling water prior to use. I've got a few at home and have been using a non-metallic cutlery and have not had the rust issue.
Did a quick measurement of the opening diameter and it's 82mm. Hope this helps!
I've always wanted one of these.
I'm just wondering, are you only meant to open it once to eat on one occasion rather than open many times?