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Alpinestars Nucleon Back Protector Insert
  • Alpinestars Nucleon Back Protector Insert
  • Alpinestars Nucleon Back Protector Insert

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Alpinestars Nucleon KR-2i Back Protector Insert

The Alpinestars Nucleon KR-2i Back Protector Insert fits all Alpinestars jackets and race suits and delivers CE Level 2 impact protection.


  • CE Certified Level 2 (EN1621-2:2014)
  • Lightweight, flexible PU injected impact foam
  • Contoured for anatomical and adaptive fit
  • Perforated for breath-ability and comfort
  • Channel ventilation system for optimized airflow

Note: Size MD is recommended for Men's jackets size 50 and smaller and XS-MD. Size LG is recommended for Men's jackets size 52 and larger and LG-4XL. See specific Women's jackets for sizing recommendations.

Sizing Info:

Waist to Shoulder (in) Height (in)  Protector Size
15 - 17 56.75 - 64.25 SM
17 - 19 64.25 - 71.75 MD
19 - 20 71.75 - 76.5 LG

Product Style RevZilla Item # Manufacturer Product # Availability
SM 973533 6501615-10-S In Stock: Ships next business day
MD 973534 6501615-10-M In Stock: Ships next business day
LG 973535 6501615-10-L In Stock: Ships next business day


Orders $39.99 and over qualify for our fast free shipping offer. Click Here for FREE Shipping Terms and Conditions.

Please see our International Orders page for orders shipping outside the US.

We show real-time availability on this product page when you select the size/color item you want.  Most items will ship the same business day an order is placed,however if an item requires additional processing time a message will be shown indicating such.

See our full Shipping Policy for further details.


If your order arrives and it is not right, we will we'll fix it, NO NONSENSE, we promise.

Doesn't fit or just not happy with it? You can return any new, unused and unaltered item within 30 business days of delivery receipt of your item. We will issue a full refund to your original payment method.

See our full Return Policy for all of the pertinent details.

Write a Product Review for a chance to win our monthly $100 giveaways.
Alpinestars Nucleon Back Protector Insert 4.8 5 71 71
Cheap Protection Bought this to go in my Alpinestars T-gp pro air jacket. Very wise purchase because I dumped my bike doing about 80 on the highway. Back was completely fine. No bruises or scrapes. This back protector still allows good airflow through your jacket and is comfortable when riding. I don't even notice it anymore. August 19, 2016
nucleon light weight, comfortable, flexible, good air flow. was a good upgrade to my alpine jacket. July 21, 2016
Great product Haven't needed to use it yet *knock on wood* But feels tough, makes me feel comfortable riding. Can't even notice it on your back. July 12, 2016
Bought it for my girlfriend, she's so happy! This product is just one word: AWESOME, i bought it for my girlfriend and she's very very happy :) June 28, 2016
FAVORITE BACK PROTECTOR EVER!!!! I want to buy one of these for every jacket and suit I have. The Dainese one is thick and hard. It suffocates me when I zip up my suit, and it makes me look like a football player when I put it in my jackets. ...then I bought this one <3333! It's thin, comfortable, and CE Level 2! June 22, 2016
Good, but standard back protector Not much to say here except for what would you expect from alpinestars? A bit thicker than I would have wanted for my Oscar Brass jacket, but feels pretty solid, breathes right and is just flexible enough to contour to my back. June 4, 2016
Great back pad upgrade! Lightweight, great airflow, CE level 2. What more is there to say. Don't trust that foam pad your jacket came with. This is a great upgrade. June 1, 2016
nice product for the price pretty sweet back insert for the price. breathable and light weight while also adding confidence of protection. June 1, 2016
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