Soft Cooler Backpack Manufacturer — Factory-Direct OEM Since 2003

Sealock is the soft cooler backpack manufacturer that wholesale buyers and brands source from factory-direct, cutting out the trading-company layer between a purchase order and the welding line. As the cooler brand of YiFuLong Outdoor Gear Co., Ltd., Sealock has welded insulated soft bags since 2003, and today runs three high-frequency welding factories across China and Vietnam. For a buyer vetting where a cooler backpack actually gets made, the difference between a real factory and a middleman shows up in the seal, the test data and the price — and this page lays out what a factory-direct OEM partner brings.

Two Decades on the Welding Line

A manufacturer's credibility is its track record, not its catalog. Sealock has built insulated soft coolers for over twenty years and welds for recognizable outdoor and lifestyle brands — including YETI, whose team has visited the Vietnam factory, alongside Stanley, Hydro Flask, Osprey, Helly Hansen and snow peak. Those relationships exist because the factory holds a consistent, audited standard, not because it is the cheapest quote.

What "Factory-Direct" Actually Gets You

Factory-direct is used loosely, so it helps to be concrete about what changes when a buyer works with the welding line instead of a reseller in front of it:

• The welding is in-house, not outsourced: the high-frequency welding that makes a cooler waterproof happens on Sealock's own lines, so the critical step is controlled rather than subcontracted to an unknown shop.
• No middleman markup: pricing comes off the factory, not a trading company adding a margin for forwarding emails.
• Direct engineering access: a brand talks to the people who develop and build the bag, which is what makes real ground-up customization possible rather than catalog rebadging.
• Quality control at the source: IQC, IPQC and OQC happen in the factory that made the parts, not as a paper check after the fact.
• Dual-origin flexibility: the same spec can be produced in China or Vietnam to manage tariffs and lead times, a lever a single-site trader cannot offer.

Inside the Manufacturing

What a factory can actually build comes down to three things: how it seals, what it insulates with, and where it can produce.

High-Frequency Welding Capability

The core capability is 27.12 MHz high-frequency welding, which bonds TPU panels and airtight zippers into a seamless, waterproof body with no needle holes. This is what separates a genuine waterproof cooler from a sewn bag with a coated zipper — and it is a capability, not a purchase, which is why it defines a real manufacturer. For how that welded seal actually works, see Cooler Backpack with Waterproof Zipper Explained.

Material and Insulation Control

Because the factory sources and cuts its own materials, it controls the spec end to end: 600D and 840D TPU laminated shells, food-grade TPU airtight membranes, and insulation from high-density XPE and EPE up to PU foam, VIP vacuum panels, EPP or aerogel for premium cold-hold. A buyer sets the tier; the factory builds to it rather than to whatever a trader has in stock.

Dual China and Vietnam Production

Sealock runs production in Dongguan, China and Ho Chi Minh City, Vietnam, with a second Vietnam line added in 2024. Building the same spec in either country lets a buyer route around tariff exposure and balance lead times — a structural advantage that comes only from owning both sites.

How to Vet a Soft Cooler Backpack Manufacturer

Many suppliers list "manufacturer"; fewer are one. Before placing an order, a buyer can separate a real factory from a trading company by checking for specific, verifiable things — each red flag below points to a capability a genuine manufacturer has and a reseller usually fakes:

• No in-house welding line: if a supplier cannot show its own high-frequency welding equipment, the waterproof step is being outsourced, and quality with it.
• Sewn seams sold as "waterproof": a stitched bag with a coated zipper marketed as waterproof signals a sewing shop, not a welding factory — the needle holes leak.
• No IPX test report: a real factory immersion-tests sealed builds and can show the result; a trader just repeats the word "waterproof."
• No gold-sample process: without an approved reference sample matched at OQC, batches drift, and a branded line arrives inconsistent.
• Thin or missing certifications: a factory that cannot pass ISO9001, BSCI or SMETA audits cannot supply serious retail buyers.
• Cannot develop from a sketch: a supplier that only rebadges catalog models has no engineering team, so a signature product is impossible.
• Single origin only: one production country means full tariff exposure and no lead-time fallback.
• Vague on MOQ, sampling and lead time: a real factory states them plainly; a middleman hedges because it is quoting someone else's line.

Sealock answers each of these directly: its own welding lines, immersion-tested IPX ratings, a gold-sample process, audited certifications, in-house development, dual-country production and stated terms.

The Range the Factory Builds

The clearest proof of a soft cooler backpack manufacturer is the backpacks it welds. Sealock's cooler-backpack range runs from a fully waterproof welded build to a high-end airtight IPX7 flagship, all real, all made on its own lines — and the factory also welds totes, fish coolers and sling styles beyond the packs shown here:

Image	Model	Type	Base Spec	Link
	Waterproof Soft Cooler Backpack	Backpack — fully waterproof	TPU welded, fully waterproof, padded straps	View
	22L IPX7 Cooler Backpack (SL-I280)	Backpack — high-end airtight	IPX7, 50 mm XPE, 48+ hrs, sternum + waist belt	View
	Insulated Cooler Backpack	Backpack — mainstream	Multi-layer EPE, waterproof zipper, ergonomic straps	View
	Soft Insulated Cooler Backpack	Backpack — welded leakproof	Fully welded leakproof body, TPU/HF	View

OEM & ODM Straight From the Line

Sourcing factory-direct means customization is engineered, not brokered. Beyond color and logo, Sealock develops a cooler backpack from the ground up — a brand brings a sketch, a sample or a target spec, and the China base carries it through sampling to a finished, original build, tuning structure, harness, capacity, insulation tier and seal level to the brief. For how outdoor brands set those specs, see Custom Cooler Backpacks for Outdoor Brands.

• MOQ 300 pcs per design, negotiable on custom.
• Sampling 7–15 days; production 30–45 days, FOB Guangdong.
• Ground-up development runs longer than a stock edit — plan against a season launch.
• China or Vietnam origin on the same spec for tariff and lead-time control.

Quality Control and Compliance

A factory-direct partner has to prove quality, not just claim it, so the checks run in-house at every stage:

1. IQC (incoming): TPU fabrics, food-grade membrane and XPE/EPE foam are verified for thickness and food-contact safety before cutting.
2. IPQC (in-process): every 27.12 MHz weld and airtight zipper join is inspected on the line.
3. Full water-immersion test: sealed builds are submerged to verify the IPX rating.
4. Load and zipper tests: a 1,500-plus-cycle strap load test and a 3,000-cycle zipper test confirm durability.
5. Color fastness & color difference: shells and logos are tested for run-to-run consistency.
6. OQC (outgoing): AQL sampling and a gold-sample comparison clear each order, with SGS or QIMA third-party inspection available on request.

Behind the line, ISO9001, BSCI, SMETA P4, GRS, HIGG and SCAN certifications keep the factory audit-ready for serious retail and brand buyers.

FAQ: Soft Cooler Backpack Manufacturer

Q: Is Sealock a manufacturer or a trading company?

A: Sealock is the cooler brand of YiFuLong Outdoor Gear Co., Ltd., a manufacturer running its own three high-frequency welding factories in China and Vietnam since 2003. The waterproof welding, quality control and product development all happen in-house, which is what factory-direct means.

Q: What is the MOQ and lead time to order factory-direct?

A: The standard MOQ is 300 pcs per design, with samples in 7–15 days and production in 30–45 days, FOB Guangdong. Production can run in China or Vietnam on the same spec to manage tariffs and lead times.

Q: Can the manufacturer develop a custom soft cooler backpack from our design?

A: Yes. Beyond color and logo, Sealock offers full ground-up development from a sketch, sample or target spec, engineering structure, harness, capacity, insulation and seal level to the brief. Ground-up builds take longer than a stock edit, so plan against the launch.

Q: How do I verify the factory's waterproof and quality claims?

A: Sealock immersion-tests sealed builds for the IPX rating, runs load and zipper cycle tests, and holds ISO9001, BSCI, SMETA P4, GRS, HIGG and SCAN certifications, with SGS or QIMA third-party inspection available. Test data and a gold-sample sign-off back the claims before shipment.

Q: Which certifications does the factory hold?

A: The factory holds ISO9001, BSCI, SMETA P4, GRS, HIGG and SCAN, keeping it audit-ready for retail and brand buyers who require compliant, socially audited production.