CORE Backpack Medium 25L
Man wearing green CORE Backpack with matching weight lifting belt wrapped around bag, inside dark gym setting.
Green CORE Backpack with matching lifting belt wrapped around
360* View of green CORE Backpack
Flat lay of gym gear that fits inside of CORE Backpack
Side profile view of green CORE Backpack
Front view of green CORE Backpack
Back view of shoulder straps on green CORE Backpack
Green CORE Backpack pockets and internal packed with laptop, weight lifting belt, bottles and workout gear
Sneakers inside green CORE Backpack shoe compartment
Shaker bottle inside green CORE Backpack bottle pocket
Green CORE Backpack chest strap worn by man in dark gym
Side by side of man and woman wearing CORE Backpack
Side by side comparison of large and medium CORE Backpack
Side by side comparison of large and medium sized CORE Backpack
CORE Backpack Medium 25L

CORE Backpack Medium 25L

4.8
Rated 4.8 out of 5 stars
4.8 Stars (226 Reviews)
$170
Size: Medium 25L
Mini 13L
Mini 13L
Medium 25L
Medium 25L
Large 33L
Large 33L
Color: Green
Black
Black
Desert
Desert
Green
Green
Natty
Natty
Limited Edition - Waxed Canvas:
Camo
Camo
Traditional
Traditional
Medium 25L Natty · Restocking Mid Feb 2026
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Matching Lifting Belt
Matching Lifting Belt
$40 $60
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PACKING A WEIGHTLIFTING BELT? THIS IS THE BACKPACK FOR YOU

  • External weightlifting belt attachment
  • 16” Internal laptop sleeve
  • Sealed internal shoe compartment
  • Dual bottle pockets

Do you even lift? If so, meet your new training partner. Say goodbye to your belt wasting space inside your bag, with this unique and specially designed lifting belt attachment that ensures bag functionality isn’t compromised whatsoever. The CORE Backpack is made for those who train hard and pack smart. 

(Lifting belt sold separately)

Covered by our guarantee to be free of defects in material or workmanship. If there is a defect in materials or workmanship KNKG will repair or replace your bag.

Our bags are meticulously designed to stand up to the test of time. We utilize durable materials, coupled with top-notch craftsmanship and rigorous testing, resulting in the toughest bags in the game. You can confidently pack your bag to its maximum capacity without worrying about it stretching or tearing.


The CORE Backpack is made from:

• 500D nylon body material (PVC backing)

• YKK zippers

• Ripstop nylon lining

• Nylon webbing

​
CORE BACKPACK
SIZE COMPARISON
Capacity
Bag Weight
Height (H)
Width (W)
Depth (D)
Shoe Storage
Laptop Sleeve
MINI
13 L / 3.4 GAL
0.8 kg / 1.8 lbs
35cm / 13.8"
25cm / 9.8"
15cm / 5.9"
Not recommended
iPad
MEDIUM
25 L / 6.6 GAL
1 kg / 2.2 lbs
50.8cm / 20"
30.5cm / 12"
17cm / 6.7"
Up to size 10
Up to 16"
LARGE
33 L / 8.7 GAL
1.1 kg / 2.4 lbs
53.3cm / 21"
31cm / 12.2"
20.1cm / 7.9"
Up to size 13
Up to 16"
Capacity
Bag Weight
Height (H)
Width (W)
Depth (D)
Shoe Storage
Laptop Sleeve
MINI
13 L / 3.4 GAL
0.8 kg / 1.8 lbs
35cm / 13.8"
25cm / 9.8"
15cm / 5.9"
Not recommended
iPad
MEDIUM
25 L / 6.6 GAL
1 kg / 2.2 lbs
50.8cm / 20"
30.5cm / 12"
17cm / 6.7"
Up to size 10
Up to 16"
LARGE
33 L / 8.7 GAL
1.1 kg / 2.4 lbs
53.3cm / 21"
31cm / 12.2"
20.1cm / 7.9"
Up to size 13
Up to 16"

This backpack is designed for serious lifters who crave serious organization.

This gym bag works harder than you do. This is the best and most functional gym bag you can find.

This is the best gym bag for powerlifters. Many amazing features that set this bag apart from its rivals. The outer material is tough, durable, and lightweight while also being water resistant and easy to clean.

FAQS

The main difference is the unique weightlifting belt attachment. This feature allows the bag be used as normal, while carrying a cumbersome lifting belt on the outside. Other changes are the volume (25L and 33L) and the layout.

Most of the materials are the same as used in other KNKG bags. YKK zippers, heavy duty buckles, nylon lining and webbing are all the same. In the CORE range, we have gone for a lighter 500D nylon outside and a new velcro logo feature that allows you to go 'incognito' with your own patches.

Measure the widest point of your belt. The CORE33 (Large) Backpack can fit a belt up to 6.3"/16cm wide. The CORE25 (Medium) Backpack can fit a belt up to 5.9"/15cm wide.

And yes! Lever belts will work with this bag.

The CORE25 (Medium) Backpack fits shoes up to size 10 US mens trainers/runners comfortably. The CORE33 (Large) Backpack fits up to size 13 US mens.

4.8
Rated 4.8 out of 5 stars
Based on 226 reviews
Total 5 star reviews: 190 Total 4 star reviews: 28 Total 3 star reviews: 5 Total 2 star reviews: 1 Total 1 star reviews: 2
96%would recommend these products
Slide 1 selected
226 reviews
  • B
    Brittney
    Reviewing
    CORE Backpack Medium 25L
    I recommend this product
    Rated 5 out of 5 stars
    5 Stars

    Ive had my eye on this backpack for some time & so far i like it.

    Was this helpful?
  • SG
    Sergio G.
    Verified Buyer
    Reviewing
    CORE Backpack Medium 25L
    I recommend this product
    What type of training is your KNKG bag supporting you with? Weightlifting
    Using For: Gym Bag
    Rated 5 out of 5 stars
    Medium bag

    Love the bag . I use it everytime I workout . I’m happy about the warranty . I just wish the belt was available . In my size ( the black one ).

    Was this helpful?
  • NS
    Nick S.
    Verified Buyer
    Reviewing
    CORE Backpack Medium 25L
    I recommend this product
    What type of training is your KNKG bag supporting you with? Weightlifting, Functional Circuit Training, CrossFit, Olympic Lifting, Bodybuilding
    Using For: Gym Bag, Sport / Fitness
    Rated 5 out of 5 stars
    Great product, even greater interaction

    I original bought a bag from KNKG that ended up having a tear in the top pocket of the bag. After reaching out to customer service and interacting with Taylor, I was able to get the Core Backup Medium 25L, which has been fantastic for my workouts! I couldn’t be more grateful and excited to use it for a long time!

    Was this helpful?
  • LS
    Lauren S.
    Verified Buyer
    Reviewing
    CORE Backpack Large 33L
    I recommend this product
    What type of training is your KNKG bag supporting you with? Weightlifting, CrossFit, Functional Circuit Training, Olympic Lifting
    Using For: Gym Bag, Sport / Fitness
    Rated 5 out of 5 stars
    The only backpack we agree on

    After decades of going through dozens of backpacks, this is the ONLY ONE that my husband (6', 210lbs) and I (5' 3", 140lbs) agree on. It is our absolute favorite not just for the thoughtful array of pockets, but because the fit works perfectly for both of our very different frames. We're each able to adjust the straps and load up the packs so that the weight is evenly distributed. Well done KNKG! We could not be more impressed!

    Was this helpful?
  • DM
    Darryl M.
    Verified Buyer
    Reviewing
    CORE Backpack Medium 25L
    I recommend this product
    What type of training is your KNKG bag supporting you with? Weightlifting, Functional Circuit Training
    Using For: Gym Bag
    Rated 4 out of 5 stars
    Molle

    Almost like being back in service, fits all my gear and comfortable on the shoulder

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Ultimate Gym Backpack with Weightlifting Belt Attachment — KNKG CORE Backpack

The CORE Backpack is purpose-built for lifters who want the convenience of a backpack with the functionality of the iconic weightlifting belt attachment. Designed for the gym, not the office, this pack carries everything you need for serious training sessions — and keeps your lifting belt secure on the outside so the inside stays free for the rest of your gear.

Why the Weightlifting Belt Attachment Matters

Lifting belts are bulky, and most backpacks aren’t built to carry them. Forcing one inside means less room for your gear. The CORE Backpack solves this with an external weightlifting belt sleeve that gives gym rats the freedom to pack properly:

  • Save Space: Belt stays outside, leaving the main compartment free.
  • Secure Fit: Reinforced sleeve and straps keep your belt secure while you move.
  • Quick Access: Pull out your belt instantly when it’s time to lift.
  • Backpack Convenience: Carry comfortably whith padded shoulder straps and a breathable back pannel.

What Fits Inside

The CORE Backpack is designed for the gym. Here’s what you can fit inside:

  • Weightlifting shoes or sneakers (dedicated shoe compartment)
  • Change of training clothes
  • Shaker bottle or water bottle (side pockets)
  • Chalk, straps, wraps, and grips
  • Knee sleeves or elbow sleeves
  • Towel
  • Headphones, small tech, or training electronics
  • Snacks or post-workout supplements
  • Phone, wallet, and keys (internal valuables pocket)

With your belt carried externally, the backpack’s interior compartments are left open for everything else you need for heavy training.

Materials & Build

  • 500D nylon body material with PVC backing
  • Ripstop nylon lining
  • Heavy-duty YKK zippers
  • Reinforced nylon webbing straps and handles

The Toughest Gym Bag Quality

Like the CORE Duffel, the CORE Backpack is built to thrive under tough conditions. Reinforced stitching, abrasion-resistant nylon, and metal hardware mean it’s made to last through years of training sessions, travel, and gym-floor abuse.

Why Choose the CORE Backpack?

  • Unique external weightlifting belt attachment
  • Purpose-built for weightlifters — not your average everyday carry backpack
  • Smart compartments: shoe zone, valuables pocket, side bottle holders
  • Built from premium, abrasion-resistant materials for unmatched toughness