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Castelli Alpha 18 Sock
Castelli Alpha 18 Sock
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Castelli Alpha 18 Sock
Castelli Alpha 18 Sock

Alpha 18 Sock

Mfg PartNum:
  (4 customer reviews)
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MSRP $24.99
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Rock Your Ride

Prepare for the ride of a lifetime with comfort and performance from head to toe. The Castelli Alpha 18 Sock pulls all the stops to create a garment that not only delivers quality and power but also style to your daily commute or weekend shenanigans.

A heavy-duty construction relies on the use of both PrimaLoft® as well as Merino wool to create a layer that delivers the perfect amount of warmth. This unique blend is also quite moisture-wicking, keeping your feet dry and odor-free. A support band along the arch maintains proper flexion and keeps your feet comfortable with every pedal.

The Alpha 18 socks are perfect for any style of ride, both day and night. The nylon heel and toe promote durability so you can go full-throttle down the gravel trail, while a reflective stripe on the back allows you to be seen in low-light conditions.


  • PrimaLoft® and Merino wool blend
  • Arch-support band
  • Nylon heel and toe for durability
  • Reflective stripe on back
  • Remarkable 18cm height

B-Stock - This product has one or more B-Stock units available. These units can be purchased at a discount (see option select). B-Stock units were returned from other customers and may have missing or damaged packaging materials. These units are otherwise as new. The full manufacturer warranty applies. Click Here for more information.

Shoe Size35-3940-4344-47   

Fabric Type: Wool / Wool Blend 


Cuff Height: Crew 

Black/Dark Gray - S/M

Mfg PartNum: R4521553010-2 

Black/Dark Gray - L/XL

Mfg PartNum: R4521553010-4 

Black/Dark Gray - 2X-Large

Mfg PartNum: R4521553010-6 

Military Green/Fiery Red - S/M

Mfg PartNum: R4521553075-2 

Military Green/Fiery Red - L/XL

Mfg PartNum: R4521553075-4 

Military Green/Fiery Red - 2X-Large

Mfg PartNum: R4521553075-6 

Savile Blue/Red - S/M

Mfg PartNum: R4521553414-2 

Savile Blue/Red - L/XL

Mfg PartNum: R4521553414-4 

Savile Blue/Red - 2X-Large

Mfg PartNum: R4521553414-6 

Ordered by Most Relevant First
5 stars
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3 stars
2 stars
1 stars
Great Looking
by BikesnBoards
Cycling Enthusiast
Cleveland, OH

I got these to match my new Emonda. The socks have padding in all the right places for comfort.

Reviewed 5/12/2022
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Stylish Socks
by Bruce CO
Cycling Enthusiast
Littleton, CO

These Castelli socks fit great - look great.

Reviewed 1/21/2022
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Comfortable - fits to size
by JJL
Cycling Enthusiast
Springfield, Illinois

Nothing to not like, these are durable 3 season cycling socks which will last a long time. Not for winter use.

Reviewed 12/30/2021
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Feet are warm
by Anonymous

Tried many socks for the colder weather. These socks have not only been comfortable but have improved the length of my ride in the colder temps.

Reviewed 1/12/2022
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