REI Co-op sock sizing
REI Co-op prints 1 chart for the models here: Mountain Merino C10726. The REI Co-op size chart page shows each one as the maker prints it, with the models that use it.
Mountain Merino C10726: Numeric ranges for this model are not available in this lookup. Open the product page’s Size chart, or choose another model with a published range here; a medium from another brand cannot settle the REI size.
Look up your size. See the fit checklist for heel position, toe room and cuff clearance.
Wash and dry REI Co-op socks
Mountain Merino C10726 allows cold or warm machine washing and low tumble drying. Do not bleach or use fabric softener.
A different instruction on the exact sock takes precedence over general brand guidance. Use the care lookup and your own drying estimate in the rotation planner.
Guarantee and return checks
We found no published guarantee from this brand. Buy on the shop’s own terms.
REI offers store and mail return routes. Bring the receipt or order-confirmation barcode for a store return. An exchange is a return followed by a new purchase. Eligibility depends on the order; no numeric return window is supplied by this lookup.