Basically made of heavier denim (16oz for indigo, 14.5oz for black), more tapered, button fly & cotton-poly threads... and a free yoyo!
These are unsanforized. I think recommend sizing would be +2 for the indigos and +0 for the blacks using Dior MIJ sizing.
Self Edge x Flat Head = SEXFH05 (Indigo)
Self Edge x Flat Head = SEXFH05BK (Black)