Name: XL / White
SKU: OS1-100547W-XL

The AC4 Active Comfort Sock uses two of OS1stâ€™s signature technologies for the ultimate comfort experience. The AC4 is built with nano-bamboo charcoal cushion where it counts and OS1stâ€™s cooling Skin Thinâ„¢ Technology for temperature regulation. Made for everything from exercise to everyday, this sock features blister protection, contoured padding, and light-to-moderate compression for support and fit. For the best fit, it is important to use the size chart before ordering.

Made with ultra-soft nylon treated with silver-ion technology for anti-bacterial odor and moisture wicking ability
Cushioned with Nano Bamboo Charcoal ionized fibers for durable softness
Skin Thin â„¢ Technology to increase air flow and temperature regulation
Seamless construction
Left/right design for anatomical fit
Y-Gore heel
Hand wash and hang dry only
Do not wash with bleach or a product that contains bleach

We offer free shipping within the US for orders over $50 (excluding Relay shoes).

Shipping FAQs

How long will it take for my order to arrive?

Most orders within the Continental U.S. arrive in 48 hours.

Sometimes certain products are not available in our stores so we are fortunate enough to be able to special order these items directly from the brands. Once an order is SHIPPED it should take between 3-5 business days for it to arrive at its destination.

Please note that these shipping timelines are only an estimate and that once an order leaves our stores, there may be carrier or customs delays that are outside our control. Additionally, we are not always able to make address changes after an order is placed, so please be sure your shipping address is correct before placing your order.

How can I track my order?

After an order has been shipped you will be sent a tracking email with a link to track your package. If you do not receive this email please email us at shoponline@runpacers.com

I recently placed an order online but haven’t received any tracking information?

Once an order has been placed you should expect to receive TWO emails. First, a confirmation email that your order has been processed and second, an email that your order has been shipped with tracking information. If you have not received any tracking information after 5 days of placing your order please email us at shoponline@runpacers.com

We gladly accept returns within 30 days of purchase. Please note that returned merchandise must have the original packaging still intact. Shoes must be in their original shoe box. Sale items are final and cannot be returned or exchanged. We cannot accept returns on any carbon fiber shoe. Refunds are issued to the original form of payment. Orders placed with store credit can only be refunded in store credit. Shipping costs are non-refundable.

If your item is damaged and your purchase date falls outside our standard return window, then please contact shoponline@runpacers.com and we’ll be happy to serve you.

Items purchased in one of our retail stores can be returned or exchanged at any store or by using our automated online return system.

Items purchased online can be returned at any store or by using our automated online return system.

Contact our customer experience team.

OS1st AC4 Active Comfort Socks No Show

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