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Insights

We are glad to share with you about the results of our work, company news, and give you timely developments and personnel appointment and removal conditions.

Welded Dry Bags 2–100L — MOQ 200, CN & VN Origin | OEM Factory
Sealock is a dry bag manufacturer in China supplying OEM, ODM, and wholesale buyers worldwide. The dry bag is the oldest and simplest product in waterproof gear — a single welded chamber closed by rolling the top — and it remains the benchmark by which a waterproof factory is judged. There is nowhere to hide: no lining to disguise a bad seam, no zipper to blame. Either the welds hold and the closure seals, or the customer's sleeping bag comes out wet. This overview covers how a dry bag is built properly, what actually causes the failures buyers hear about, and the sourcing terms.
2026-08-20
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Waterproof Phone Pouch Material Guide for Buyers
Sealock is a waterproof phone pouch manufacturer and OEM supplier. A phone pouch is not made of one material — it's a body film, a transparent window, a gasket, and lock hardware, and each is chosen separately. Buyers usually ask "PVC or TPU?" as if that settles it, when the questions that actually decide the outcome are film thickness, clarity retention, gasket elasticity, and compliance. This guide covers each component, what the real trade-offs are, and where the commercial risk sits.
2026-08-20
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Will the Colour Come Off on Your Shirt?
DONGGUAN, China — [August], 2026 — Here's a complaint no factory wants to receive. The bag is fine. It's welded, it's sealed, it holds water out exactly as promised. The problem is the customer's white t-shirt, which now has a faint stripe of the bag's colour across the back — and the passenger seat of their car, which has a matching one.Colour transfer is a small failure with a long tail. It doesn't stop the product working, so it never shows up in a waterproof test or a load test, and it's almost never specified in a purchase order. It just quietly turns a good product into a returned one. The machine in this article exists to catch it before it ships.AATCC crockmeter in the Sealock in-house laboratory.The motorized crockmeter in Sealock's lab, with its controlled operating procedure posted at the machine.
2026-08-13
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The Number That Decides Whether a Weld Is Actually a Weld
DONGGUAN, China — [Month Day], 2026 — Everything this company builds rests on one claim: that two pieces of coated fabric, fused together by high-frequency welding, will behave as a single piece of material for the life of the product. Every dry bag, every cooler, every inflatable buoy is that claim repeated a few hundred times around a seam.It's a claim you can't verify by looking. A perfect weld and a marginal weld look identical from the outside — the difference only shows up months later, when the marginal one starts to peel apart in a customer's hands. Which is why the machine in this article exists, and why, of everything in our lab, it's the one that most directly measures whether our core process is working.It pulls the weld apart and tells you exactly how hard it had to try.
2026-08-13
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3,000 Pulls, Under Load: How We Test the Part of a Bag That Fails First
DONGGUAN, China — [Month Day], 2026 — Ask any bag factory where the warranty claims come from and you'll get the same answer, delivered with a sigh. Not the fabric. Not the seams. The zipper.It makes sense when you think about what a zipper is: the only part of a bag with dozens of moving components, operated several times a day, every day, usually with one impatient hand, often while the bag is stuffed past the point of reason. Everything else on a bag sits still. The zipper works for a living.So in our lab there's a machine whose entire job is to open and close zippers until something gives. In the photograph its counter is set to 3,000 cycles. It will run all of them, under measured load, and then stop by itself.
2026-08-12
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How Waterproof Phone Pouches Are Tested (IPX7 vs IPX8)
Sealock is a waterproof phone pouch manufacturer and OEM supplier. Every pouch on the market is described as waterproof; far fewer have been tested in a way that means anything. The gap matters more here than in any other waterproof product, because the customer isn't risking a wet towel — they're risking their phone. This guide walks through how a phone pouch is actually tested, from the international standard behind the rating to the checks on the production line, the final shipment inspection, and the three-minute test a buyer can run themselves.
2026-08-12
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