BEWARE Larger & bulkier than Sorels
Purchased for my Sorels. Measured by Sorel liners and chose size to match.  These liners are wider and cut broader over the instep (ankle to top of foot) so they are too bulky to fit into (what I used to think of as very bulky block-like) Sorel boots.  The upshot is they do not fit into the boot and the shipping is so expensive that I will use them as slippers instead.
Rating: 2 stars