Waterproof Tube Dry Bag with Transparent Window and Zip Pocket

Why a Viewing Window Changes How a Dry Bag Gets Used

An opaque roll-top has a hidden cost that only shows up in the field. To check whether the spare fleece is in there, you unroll the closure — often with wet hands, often on a moving boat — and then you have to roll it back correctly under time pressure. Every one of those cycles is an opportunity for water to get in, and the failures people blame on the bag usually happened during an unnecessary opening.

The welded PVC window removes most of those openings. Contents are identifiable at a glance, so the bag gets opened when something is actually needed rather than when the packer's memory fails. For rental fleets and outfitters this matters twice over: staff can verify contents at handover without breaking the seal, and customers who have never used a roll-top are not repeatedly re-rolling a closure they do not understand.

Dry-Wet Separation Without Compromising the Main Seal

The zip pocket is deliberately outside the waterproof chamber. That is the point. A wet swimsuit, a used towel, a muddy pair of sandals, or a dripping fishing glove all need somewhere to go, and putting them in the sealed compartment defeats the entire purpose of carrying a dry bag.

With the pocket separated, the main chamber holds only what must stay dry — spare clothing, electronics, documents, a camera body — while everything wet stays on the outside of the waterproof line. The pocket is also where small items belong that would otherwise sink to the bottom of a 20-litre tube and require a full unroll to retrieve.

500D PVC Tarpaulin — What the Number Actually Means

The 500D specification describes the denier of the base fabric scrim laminated between PVC layers. Higher denier means thicker yarn, and thicker yarn means the fabric resists abrasion and tearing rather than relying on the PVC coating alone. It is the difference between a bag that survives being dragged across a gunwale or a gravel launch and one that develops pinholes in its first season.

The material also matters for how the bag is joined. PVC tarpaulin can be high-frequency welded, which fuses the two layers into a continuous material rather than joining them with thread. There are no needle penetrations anywhere in the body, so there is no seam tape to peel, no stitch line to wick water, and no gradual leakage as the sealant ages. On a stitched-and-taped bag, the tape is the weakest component and the first to fail; on a welded bag, that failure mode does not exist.

The Roll-Top Closure and How to Get IPX7 From It

A roll-top is a compression seal, not a mechanical one. Waterproof performance is produced by the pressure of the rolled material against itself, which is why the same bag can pass or fail depending entirely on how it was closed. Two facts govern the outcome.

First, expel excess air but not all of it before rolling — pressing the opening flat gives the roll a clean flat face to compress against, while leaving some air in the chamber is what keeps the bag buoyant. Second, roll at least three full turns. One or two turns produce a closure that looks shut but has no sealing pressure; the third turn is where the compression becomes real. Clip the buckles across the roll to lock it, and the bag will withstand a full water-immersion test of 2+ hours consistent with its IPX7 rating.

1. Load the main compartment, leaving a hand's width of empty material above the contents.
2. Press the opening flat, aligning the two edges so the seal band meets evenly.
3. Roll down at least three full turns, keeping the roll tight and even across its width.
4. Bring the ends together and clip the POM buckles to lock the roll in place.
5. Check that the rolled band lies flat with no ridge or gap at either end.

Floating Capability

Because the rolled chamber retains air, a correctly closed SL-D693 floats when loaded with typical soft gear. This is a recovery feature rather than a flotation device — it buys the minutes needed to retrieve a bag after a capsize instead of watching it sink out of reach. The yellow colourway exists for the same reason: a black bag on moving water is difficult to spot, and buyers supplying rental or guided operations should weigh visibility against aesthetics.

Buoyancy depends on load. A bag packed solid with dense contents and rolled with all air expelled will not float, so operators who rely on this property should brief users to leave headspace when rolling.

Capacity Guide

Roll-top capacity is nominal and measured before rolling — the three turns needed to seal consume roughly the top fifth of the tube. Both sizes below are stated at nominal volume, with realistic loads listed to help you specify the right size rather than discovering it after the first container arrives.

Product Specifications

Dimensions

Materials & Hardware

Where It Gets Used

Customization for Brands and Buyers

SEALOCK has built waterproof gear for over 20 years, with production in Dongguan, China and Ho Chi Minh City, Vietnam. Among the brands we manufacture for are OSPREY, KAILAS, CHUMS, and snow peak — companies whose specifications tend to be exacting, which is the standard our tooling and QC are set up around.

On this platform, most requirements can be met. Logo application and colourway changes are routine. Beyond that, we develop from the ground up: altered tube proportions, additional capacities outside the 15L/20L pair, repositioned or resized viewing windows, a second pocket, D-ring or lash-point additions, alternative webbing widths, and different hardware specifications. Ground-up structural development carries a longer schedule than branding work, and we will tell you what that schedule genuinely is when we quote rather than after you have committed to a launch date.

How the Bag Is Built

The production sequence below exists to make performance repeatable across batches — the thing that separates a factory sample from a container that behaves the same way.

Testing and Inspection

Inspection runs at three points — IQC on incoming materials, IPQC during welding and assembly, and OQC before the container is sealed. SGS or QIMA third-party inspection can be arranged on request, and customers running their own protocol are welcome to execute it in full on site: unboxing, vacuum extraction, 24-hour static rest, and air-leak determination.

Questions Buyers Actually Ask

Is IPX7 enough, or do I need IPX8?

IPX7 covers immersion — capsizes, dropped bags, swamped cockpits, sustained rain. IPX8 describes deeper or longer submersion and is not what a roll-top closure is designed to deliver, because roll-tops seal by compression rather than by a mechanical lock. For paddle sports, fishing, and beach use, IPX7 is the appropriate specification.

Why did my dry bag leak?

In the overwhelming majority of cases the bag was rolled fewer than three turns, or one end of the roll was looser than the other. Water enters at the corner of a slack roll. The second most common cause is over-packing, which leaves too little material above the contents to roll properly.

Will the transparent window crack over time?

Clear PVC film stiffens with UV exposure and cold. Storing the bag rolled tight through a winter and then unrolling it in cold weather is the scenario to avoid. Stored flat and out of direct sunlight, the window outlives the rest of the bag.

Is the zip pocket waterproof?

No, and intentionally so — it sits outside the sealed compartment for wet items. Anything that must stay dry belongs in the main chamber.

Does the bag really float?

With normal soft-gear loading and air left in the chamber before rolling, yes. Packed dense and fully compressed, it will not. Brief end users on leaving headspace if buoyancy is part of your product claim.

Can the strap be removed?

Yes. The reinforced webbing strap detaches, which suits deck-lashed and in-hatch use where a loose strap is a snag hazard.

Can you produce capacities other than 15L and 20L?

Yes. Additional capacities, altered proportions, and repositioned windows are all standard ODM work. Contact us with your target sizes and we will quote tooling and schedule.

What is the minimum order quantity?

300 pieces. For mixed-size or mixed-colour orders and project-specific requirements, write to info@sealock.com.hk.

Keeping It Serviceable

PVC tarpaulin is forgiving material, and the failure modes it does have are predictable and avoidable.

• Rinse with fresh water after saltwater use; salt crystals left in the closure band act as an abrasive every time the bag is rolled.
• Dry the bag inside out and store it loosely rolled or flat — never compressed tight for long periods.
• Keep it out of prolonged direct sunlight; UV is what eventually stiffens both the tarpaulin and the clear window.
• Vary the roll line slightly between uses so a single crease does not become a permanent fold.
• Clean with mild soap and water only. Solvents and alcohol-based cleaners attack PVC plasticisers.
• Small punctures can be patched with PVC repair adhesive; welded seams cannot be field-repaired, so protect them from abrasion.

Safety Notes

Packaging & Shipping

Packaging is specified to your channel — bulk poly for outfitter and promotional volume, header card or retail box for shelf presentation. Carton quantity and dimensions vary by capacity and are confirmed at quotation.