Man wearing black CORE Backpack in gym
Black CORE Backpack with matching lifting belt sitting on wooden box
360* views of black CORE Backpack
Flat lay of gym gear that packs inside CORE Backpack
Black CORE Backpack sitting on wooden box
Side view of black CORE Backpack
Back view of shoulder straps and chest strap on black CORE Backpack
Internal of CORE Backpack packed with lifting belt, drink bottles and workout gear
Shaker inside black CORE Backpack bottle pocket
Sneakers inside black CORE Backpack shoe compartment
Side by side comparison of man and woman wearing KNKG 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 (144 Reviews)
$169.95
Size: Medium 25L
Mini 13L
Mini 13L
Medium 25L
Medium 25L
Large 33L
Large 33L
Color: Black
Black
Black
Desert
Desert
Green
Green
Natty
Natty
Limited Edition - Waxed Canvas:
Camo
Camo
Traditional
Traditional
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Lifting Belt
Lifting Belt
$39.95 $59.95
KNKG HERITAGE Leather Wallet
KNKG HERITAGE Leather Wallet
$49.95 $59.95
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BUILT FOR LIFTERS & SERIOUS ORGANIZATION

  • 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 promise to be free of defects in material or workmanship within its practical lifetime. If there is a defect in materials or workmanship KNKG will repair or replace your bag, including free shipping.

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

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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 144 reviews
Total 5 star reviews: 124 Total 4 star reviews: 15 Total 3 star reviews: 2 Total 2 star reviews: 1 Total 1 star reviews: 2
97%would recommend these products
Slide 1 selected
144 reviews
  • JG
    John G.
    Verified Buyer
    Reviewing
    CORE Backpack Mini 13L
    I recommend this product
    What type of training is your KNKG bag supporting you with? None - I don't use my bag for training
    Using For: Work
    Rated 5 out of 5 stars
    Great little bag

    Bought this bag for work and it’s exactly what I needed. Not too big, not too small. Just right for what I needed. Great construction with numerous pockets.

    Was this helpful?
  • CR
    Christopher r.
    Verified Buyer
    Reviewing
    CORE Backpack Medium 25L
    I recommend this product
    What type of training is your KNKG bag supporting you with? None - I don't use my bag for training
    Using For: Every Day Carry
    Rated 5 out of 5 stars
    Unique

    This bag stands out. Keep it with me like cellphone. This won't be my last bag.

    Was this helpful?
  • YG
    Yessenia G.
    Verified Buyer
    Reviewing
    CORE Backpack Mini 13L
    I recommend this product
    What type of training is your KNKG bag supporting you with? Weightlifting, Functional Circuit Training
    Using For: Gym Bag, Every Day Carry, Work
    Rated 5 out of 5 stars
    Amazing

    Super comfortable bag. Feels very durable. Very organized. I love it

    Was this helpful?
  • JP
    John P.
    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
    Backpack- Green

    Very good quality backpack, the 25L bag fits all of my gym necessities in addition to my work belongings. Backpack looks aesthetically pleasing as well.

    Was this helpful?
  • S
    sinbae
    Reviewing
    CORE Backpack Medium 25L
    I recommend this product
    Rated 5 out of 5 stars
    5 Stars

    Good

    Was this helpful?
Show More

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