Men's Siskin 12 Hydration Backpack

SKU: 10005103

Regular price$140.00
  • In stock, ready to ship
  • Inventory on the way
  • Free shipping on all orders $49+

Designed for adventurous days on the trail, the Siskin 12-liter pack offers a well-balanced performance for mountain bikers seeking a little extra room and focused features. Equipped with a next-gen 2.5-liter reservoir, it ensures you stay hydrated during your longest rides, while its spacious main compartment provides ample space for spare tubes, multi-tools, trail pumps, extra layers, and more.

Featuring upper-side compression and options for both traditional LidLock helmet carry and full-face helmet carry with compression straps, the Siskin offers versatility and convenience. Its U-zip main compartment access and front fabric shove-it pocket make it easy to access your gear, while the included Hydraulics LT 2.5 L reservoir ensures you have plenty of hydration for the journey.

Designed with bike-focused features in mind, this pack offers just the right volume for any ride, along with main compartment tool organization to keep your essentials easily accessible. The rolled, soft-edged harness and air mesh wrap hipbelt ensure a comfortable and stable carry, while the zippered hipbelt pockets provide additional storage options.

Constructed with Osprey's renowned quality and attention to detail, the Siskin is built to withstand the demands of mountain biking. Its AIRSCAPE™ suspension system and backpanel provide maximum ventilation while keeping the load close to the body, ensuring you stay cool and comfortable throughout your ride. With its thoughtful design and bike-specific features, the Osprey Siskin 12 is the perfect companion for all your trail adventures.

Osprey Siskin 12 Features:

  • Upper-side compression and full-face helmet carry
  • Direct access zip path to reservoir compartment
  • U-zip main compartment access
  • Front fabric shove-it pocket
  • LidLock helmet attachment
  • Blinker light attachment
  • Magnetic sternum strap bite valve attachment
  • Hydraulics LT 2.5 L reservoir included
  • Main compartment tool organization
  • Zippered hipbelt pockets
  • Zippered scratch-free heat-embossed slash pocket

Tech Specs:

Volume: 732 IN 3 / 12 L
Dimensions:  8.7H X 9.1W X 18.5D IN
Weight: 1.918 LBS
Fabric: Main & Bottom: Bluesign® approved 100% recycled 400D high-tenacity nylon, DWR treatments made without PFAS

Please reach out to us with any questions you may have on anything we sell. We want to make sure you get the right part the first time. Our lifelong riders at Thunder Mountain Bikes are knowledgeable and would love to talk to you!


We currently offer both economy and expedited shipping options though FedEX and USPS. 

Orders totaling over $49 are eligible to ship for free via an economy ground option of our choice. 

If you're in need of something super-quick, please contact us directly. We may be able to overnight your order with an additional fee and depending on your location. 


Should there be an issue with the item you bought, or you no longer need your purchase, we will be happy to set up a return.

Returns or exchange requests for New or Used Bikes must be requested by emailing us at within fifteen (15) days from the date of delivery. Bikes must be in un-ridden condition. Custom-built bikes may not be returned. Returned bikes have a $200 restocking fee and the customer pays for return shipping.

Returns for most other items may be requested within sixty (60) days of the delivery date. All returned items must be received in new, unused, and uninstalled condition, with the original tags and labels attached and in the original packaging. We cannot accept returns on any items installed or show wear of any kind. 

Clearance and open-box items may not be returned. 


To request a return, please log in to your customer account by clicking the  customer account icon  Profile icon in the top right of any page or visit

1. In the Email field, enter your email address and click Continue.

2. In your email account, open the email sent from our store and copy the six-digit verification code included in the email.

3. Go back to the online store and enter a six-digit verification code to log in.

4. Find and click on the order that you want to submit a return for.

5. If your order has more than one item, select only the items you want to return.

6. Select a return reason and add a note for the store if needed.

7. Click Request Return.

Once your return request is approved, you will receive an email with shipping instructions and a return shipping label. 


We will process your return after we receive your returned item(s) and inspect the condition. Please allow at least seven (7) days from the receipt of your item to process your refund. We will notify you by email when your return has been processed.


If you receive defective or damaged products or if we sent you the wrong products, please contact us using the phone number or email below.


If you have any questions concerning our return policy, please contact us at:

(928) 282-1106   |

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