Do not buy this item, a complete waste of money. It is nearly impossible to take out and reinstall the heat packs. The odor is terrible! It nearly knocked me over when I opened the box. I paid $6.95 to have them shipped and now they want $6.95 to ship them back. I would be paying $13.90 to get my $12.99 back - and I have no slippers. That is assuming they would refund my $12.99. I don't trust them to do so. I will save my $6.95 and bury the slippers in the back yard. Clear the Shelves obviously has a warehouse full of junk they want to get rid of. Amazon is usually so good, I cannot believe they let this outfit use their web site.