Natural and beige leather watch straps in undyed Horween hides, the ones that patina fastest. Shell cordovan, Chromexcel, Cypress and Waxed Flesh.
Undyed leather shows every hour of wear. These start pale honey and darken toward tan within a season.
Natural is the leather with no color added: what comes off the tannery's finishing line before any dye. Natural shell cordovan is a pale honey that darkens faster than any other cordovan color. Natural Chromexcel and Natural Cypress start a shade warmer. Natural Waxed Flesh is the roughout, a pale nap under wax that burnishes where it's handled.
With nothing covering the surface, an undyed strap records everything: sun, skin oils, the cuff it rubs against. Within a season it's moved toward tan, and by the second year it's a mid brown no dyed strap could copy. Expect marks and darkened edges early on. That's the patina starting, and it evens out as the rest catches up.
The shell cordovan strap is unlined; the other three are lined. All come in 12 to 24mm, straight or tapered, and three lengths or a custom one. Cream thread is the default here; the sizing guide covers width and length.