I have not yet had the chance to test this item as far as smell proof goes but I am confident that it will function as promised. It is however, not possible to open this stash box as advised in the included instructions by placing your fingers around the box and lifting the lid with your thumbs. I have tried many times. The light weight of the plastic box just lifts the entire container with the attempt to open the lid. The only way I was able to open the lid was to bear hug the lower container ...