Barrel Cooler Backpack 18L – Insulated Soft Cooler Backpack with Flip Lid and Waist Strap, SL-I309

At a Glance

Product Description

SL-I309 is an insulated barrel cooler backpack measuring 34 × 23 × 47 cm outside and 28 × 17 × 39 cm inside, holding about 18 liters, or around 20 standard 330 ml cans without ice. It weighs about 1.3 kg. The body is an upright oval barrel in TPU laminated waterproof fabric over closed-cell EPE foam, with a food-grade waterproof liner, and the seams are high-frequency welded. The top is a rounded flip lid that opens on a zip running around the rim. A flat slip pocket sits on the side panel for a phone, keys or napkins, and the base is reinforced with a black wear band. The harness has padded shoulder straps with mesh lining, a sternum strap and a waist strap with a side-release buckle. The standard colourway is coral pink with forest green straps and pocket; other colours can be produced to order.

Barrel Shape

Most backpack coolers are rectangular boxes with sharp corners. SL-I309 is built as a rounded oval barrel instead. The curved walls sit closer to the back and the shoulders, so the load stays nearer the wearer's centre of gravity and the cooler does not swing out when walking or climbing steps. Inside, the rounded corners leave no dead space where ice bridges or crumbs collect, so ice settles evenly around the contents and the liner is easy to wipe out. The tall, narrow profile also takes up little floor space on a boat, beside a beach chair or behind a car seat.

Size and What Fits

The interior is 39 cm tall, which takes standard wine bottles and 1.5 L drink bottles standing upright. At 28 × 17 cm across, it holds around 20 cans without ice, about 14 cans with enough ice to keep them cold, or lunch and drinks for two to three people for a day. For a family day at the beach or a full tailgate, a larger cooler from the range below is the better fit; for a day hike, a picnic for two or a walk to the pool, 18 L is enough without the weight of a bigger cooler.

Carrying and Fit

A full cooler with ice weighs around 10–12 kg, and how it carries matters as much as how cold it stays. The shoulder straps are padded and lined with breathable mesh. The sternum strap clips across the chest and stops the straps sliding outward, and the waist strap holds the base of the cooler against the lower back, so it does not bounce on uneven ground or swing when you lean forward to set it down. All three adjust for different torso lengths and over thicker clothing. Both buckles release with one hand when the cooler comes off.

Construction and Water Behaviour

The body seams are high-frequency welded, joining the TPU panels into a single layer of material with no needle holes along the walls. The strap anchors are mounted on reinforced panels rather than stitched through the cold compartment, and the shoulder straps themselves are sewn, which is how they get their padded, contoured shape.

The cooler is water-resistant. The TPU shell and the flip lid shed rain, spray and splashes, and the welded liner keeps melt-water inside while the cooler is upright. The zip is a water-resistant zip rather than an airtight one, so the cooler should be kept upright when it holds melt-water, and it is not designed to be submerged. An airtight zip can be specified on custom orders for leakproof performance in any orientation.

Cold Holding

Packed with ice, closed and kept out of direct sun, the cooler holds ice for approximately 24–36 hours in our trials at 25 °C ambient. The lower figure applies to frequent opening and warmer conditions, the higher figure to a pre-chilled cooler opened only a few times. Results change with ambient temperature, sun exposure, how often the lid is opened and whether the contents were chilled before loading. Pre-chilling drinks and keeping the cooler in shade make the biggest difference.

Choosing a Backpack Cooler

Image	Model	Capacity	Dimensions (H × W × D)	Weight	Construction	Use
	SL-I309	approx. 18 L	47 × 34 × 23 cm 18.5 × 13.4 × 9.1 in	1.3 kg / 2.9 lb	Welded TPU oval barrel; zip-around flip lid, water-resistant; sternum and waist straps	Day trips, picnics, beach for 2–3 people
	SL-I075A	approx. 22 L	51 × 33 × 24.5 cm 20.1 × 13.0 × 9.6 in	1.9 kg / 4.2 lb	Welded TPU box; airtight zip, IPX7; sternum strap and hip belt	Longer carries, leakproof in any position
	SL-I118	30 L backpack, 12 L insert	50 × 32 × 20 cm 19.7 × 12.6 × 7.9 in	1.8 kg / 4.0 lb	Welded TPU backpack with removable welded cooler insert; IPX6; sternum and waist straps	One bag for cold food and dry gear
	SL-E050B	approx. 25 L	32 × 37.5 × 26.5 cm 12.6 × 14.8 × 10.4 in	1.4 kg / 3.1 lb	Welded TPU flat-walled box; moulded flip lid, water-resistant; padded shoulder straps	Vending and printed promotional programmes

Engineering Specifications

Material Specifications

Functional Specifications

Customization and OEM

Packaging Specifications

Recommended Use

Beach days, picnics, park outings, day hikes, festivals, pool trips and boat days where the cooler has to be carried on foot. Suitable for drinks, food and ice for two to three people. Not intended for submersion.

Care and Maintenance

Empty the cooler after each use, wipe the liner with warm water and mild detergent, and leave the lid open until it is completely dry before storing; most odour complaints with soft coolers come from storing them closed while damp. Rinse off sand and salt after beach or boat use, and keep the zip teeth clean so the slider runs smoothly. Store the cooler out of direct sun when not in use, which keeps the TPU and the colours looking new for longer.

Quality Inspection Standards

Every production run is checked at IQC, IPQC and OQC. The suite covers load testing to 1,500 cycles, zipper fatigue to 3,000 cycles, tensile and bonding strength on welded seams and strap anchors, seam strength and bar-tack pull tests on the sewn harness, buckle pull and release testing, abrasion on the base, colour fastness and colour difference against the approved sample, and rain and water-jet testing on finished coolers. Third-party inspection by SGS or QIMA can be arranged at the buyer's cost.

Product Highlights

Oval barrel body that carries close to the back and has no inside corners. 39 cm interior that takes wine and 1.5 L bottles upright. High-frequency welded TPU body with EPE foam and food-grade liner. Rounded flip lid on a zip-around top. Padded mesh-lined straps, sternum strap and waist strap for a stable carry. Side slip pocket and reinforced base. Coral pink and forest green, with two-tone custom colours at MOQ 300.

Printing and Logo

The curved front of the barrel takes a large logo or full artwork. Screen printing suits solid one- to three-colour marks, heat transfer handles multi-colour artwork, and UV digital printing reproduces photography and gradients across the curve. Welded TPU patches and raised silicone prints give a tonal, textured mark, and woven labels can be sewn onto the shoulder straps. The two-tone layout lets the body and harness carry different brand colours. Artwork is required as vector files; a digital placement proof is returned before sampling.

OEM / ODM Capability

Sealock has manufactured insulated and waterproof gear for over 20 years, with factories in Guangdong, China and Ho Chi Minh City, Vietnam — the second site giving brands a non-China origin option where tariff exposure matters. We hold ISO 9001, BSCI, SMETA, Higg, GRS and SCAN certification, and produce insulated products for brands including STANLEY, Hydro Flask and CORDOVA.

The cooler body is high-frequency welded, while the shoulder straps, sternum strap and waist strap are sewn, and sewn construction is an equally mature in-house capability rather than an outsourced step. A backpack cooler depends on both. Most demanding requirements can be met, from a new two-tone colourway to an airtight zip, a padded hip belt, new sizes or full custom development; complex development with new tooling adds time to the first sample cycle, which is worth planning for early.

Related Products

• Backpack Cooler 22L – Airtight Zip, Hip Belt
• Cooler Backpack with Removable Insert – 2-in-1
• Ice Cream Insulated Soft Cooler Backpack
• Custom Backpack Cooler – OEM & Private Label
• Waterproof Soft Cooler Backpack

FAQ

What is the minimum order quantity?

300 pieces per colour.

What does it cost?

Price depends on quantity, insulation, closure, accessories and logo method. Send your specification to info@sealock.com.hk and we will quote within one working day.

Can we put our own logo on it?

Yes. Screen print, heat transfer, UV digital print, welded patches and raised silicone prints go on the body, and woven labels can go on the straps. Body and harness colours can be matched to your brand.

How many cans does it hold?

About 20 standard 330 ml cans without ice, or about 14 with ice.

Will a wine bottle fit?

Yes. The interior is 39 cm tall, which takes standard wine bottles and 1.5 L drink bottles upright.

Is it leakproof?

The welded liner keeps melt-water in while the cooler is upright, and the shell resists rain and splashes. The zip is water-resistant rather than airtight, so keep it upright when full of melt-water. It is not submersible. An airtight zip can be specified on custom orders.

How long does ice last?

Approximately 24–36 hours in our trials at 25 °C ambient, packed with ice, closed and out of direct sun. Frequent opening and direct sun bring it toward the lower figure.

Is it comfortable to carry when full?

The padded mesh-lined straps, sternum strap and waist strap keep the barrel close to the back and stop it from bouncing. Keep loads under about 12 kg for longer walks.

Why a barrel shape?

The rounded body carries closer to the back than a box, leaves no inside corners for ice to bridge or dirt to collect, and takes up less floor space.

What is the lead time?

Samples in 7–15 days. Production is 30–45 days after sample approval.

Request a Quote

Send your target quantity, colourway and logo artwork to info@sealock.com.hk. We will return a quotation with sample lead time and packaging options.