DryVault, GripTrek and Nubora: What Kiwi's Boot Technologies Do

DryVault is the sealed waterproof bootie inside every Kiwi boot labeled waterproof. GripTrek is the slip and oil resistant lugged outsole on every Kiwi boot. Nubora is a two-layer EVA and PU cushioning system in our Rugged black full grain leather 6-inch boots and the ProGuard.

Kiwi boot technology names describe how a boot is built. They are not safety ratings. The ratings, such as ASTM F2413-24 I/75 C/75, EH and SR, are listed separately under Specifications on each boot page, and they are what to check against the hazard assessment your employer does under 29 CFR 1910.132(d).

DryVault: how a waterproof bootie works

DryVault is a sealed internal waterproof bootie: a waterproof layer built inside the boot, around the foot.

A bootie solves a problem the upper can't. An upper is made of panels joined by seams, and every seam is a row of needle holes. Give standing water enough time and it finds those holes. DryVault adds a sealed barrier inside the boot, so water that gets through the upper still has the bootie to pass before it reaches the foot.

It does have a limit. DryVault cannot stop water that comes in over the top of the collar. A crew pouring footings after two days of rain should match boot height to the depth they'll actually stand in, because once water tops the collar, it's inside the bootie with the foot.

Waterproof vs water resistant Kiwi boots

Every Kiwi boot labeled waterproof has DryVault, in composite toe, steel toe and soft toe styles, from the Rugged tactical boots to the Premium cap-toe work boots. Look for Waterproof in the product name in our footwear collection.

Water resistant styles rely mainly on the upper construction to shed water. That covers a lot of work that doesn't involve standing in water. A water resistant boot handles wet grass and a damp shop floor, and it's a year-round boot for dry sites and warm-weather jobs.

The deciding question is whether your crew stands in water. If they do, choose DryVault. Our guide to waterproof vs water resistant work boots goes further into the trade-offs.

GripTrek: the slip and oil resistant outsole

GripTrek is Kiwi's outsole program, a slip and oil resistant lugged outsole made for traction on mixed surfaces. Every Kiwi boot has it.

A lugged outsole generally does two jobs. The lug edges bite into soft or uneven ground. The channels between lugs give water and oil somewhere to go, so on a shop floor where hydraulic fluid has dripped, the rubber keeps more contact with the concrete instead of riding on a film of liquid.

GripTrek comes in two constructions:

• Cemented EVA and rubber MD outsole: used on most Kiwi boots. The EVA layer keeps the sole light and flexible, and the rubber carries the tread. It suits boots you walk and climb in all day.
• Heavy-duty rubber lug outsole on Goodyear welt construction: used on the Premium cap-toe boots. It trades some weight and flex for durability and stability on rough ground.

GripTrek is a construction name. Slip resistance is tested and listed separately: every Kiwi boot is SR rated to ASTM F3445. A slip resistant outsole reduces slip risk but doesn't eliminate it, and once the tread wears smooth, the boot is due for replacement.

Nubora: the two-layer cushioning system

Nubora stacks two materials: a flexible EVA midsole underneath, and an ultra cushioned mesh and PU insole on top, with a heel-to-toe drop.

The two foams cover for each other. EVA compresses easily and springs back fast, which makes it good at taking the first hit of each heel strike, but it can pack down over time. PU is denser. It rebounds more slowly and holds its shape longer. Stacking them puts the EVA under the foot to absorb impact and the PU against the foot for support that lasts. It matters most in the eighth hour on a concrete warehouse floor.

The heel-to-toe drop means the footbed sits slightly higher at the heel than at the forefoot. It is meant to help the foot roll from heel to toe through each step.

Nubora is in the Rugged black full grain leather 6-inch boots, in composite toe, steel toe and soft toe versions, and in the ProGuard.

Every Kiwi boot technology at a glance

DryVault, GripTrek and Nubora come up most often, but Kiwi boot pages use several other names. Here is what each one is and where you'll find it.

The ProGuard carries DryVault, GripTrek, Nubora, ScuffShield, Veldura, Aramor, YTorq, MorphFit and Aferra, with a PR rating from its Aramor plate. For the full write-up on each name, see our technology and materials page.

Where to see DryVault, GripTrek and Nubora together

The Rugged black composite toe waterproof boot is the clearest example. It combines DryVault, a cemented GripTrek EVA and rubber MD outsole and Nubora cushioning, with a YKK zipper on the inner side and 200g 3M Thinsulate insulation. It is ASTM F2413-24 I/75 C/75 compliant, EH rated and SR rated.

For a Goodyear welt boot with the heavier GripTrek lug sole, DryVault and a ScuffShield toe, look at the Premium wheat nubuck composite toe waterproof cap-toe boot. Nubuck needs its own care routine, and our guide to cleaning and caring for leather work boots covers both smooth leather and nubuck.

Matching boot technology to the job

• Standing water, mud, slush or snow: choose a boot labeled waterproof, which means DryVault.
• Long shifts on concrete: look for Nubora in the Rugged black full grain leather boots.
• Oily shop floors or loading docks: every Kiwi boot has GripTrek and an SR rating, so the job is checking tread wear often.
• Rough ground and uneven footing: consider the Premium cap-toe boots with the Goodyear welt lug sole.
• Nails and screws underfoot: you need a PR rated boot. The ProGuard is ours, and its Aramor plate provides the rating.
• Cold sites: every Kiwi boot has 200g 3M Thinsulate insulation.
• Dry, warm-weather work: a water resistant boot may be all you need.

Still deciding between styles? Put them side by side on our footwear comparison page, then check the safety ratings your site requires against each one.

Frequently asked questions

What is a waterproof bootie in a work boot?

A waterproof bootie is a sealed, sock-shaped waterproof layer built inside the boot. It keeps water that gets through the seams of the upper away from the foot. In Kiwi boots, this bootie is called DryVault, and every Kiwi boot labeled waterproof has it.

Will waterproof work boots keep my feet dry in deep water?

Only up to the collar. A waterproof bootie can't stop water that pours in over the top of the boot. Match boot height to the depth of water your crew actually works in.

Is GripTrek the same as an SR rating?

No. GripTrek is the name of Kiwi's lugged outsole construction. SR is a tested rating to ASTM F3445, listed separately under Specifications, and every Kiwi boot carries it.

Which Kiwi boots have Nubora cushioning?

Nubora is in the Rugged black full grain leather 6-inch boots, in composite toe, steel toe and soft toe versions. The ProGuard has it too.

Are Kiwi work boots insulated?

Yes. Every Kiwi boot has 200g 3M Thinsulate insulation. That applies to waterproof and water resistant styles alike.

Equipping a crew with Kiwi boots

When the order covers several styles and a full run of sizes, a quote is faster than a cart. Start a crew quote and list the boots and sizes you need. If the same crew needs hi-vis, we can print your logo on any Kiwi hi-vis gear with a 12 item minimum. Retailers who want to carry Kiwi boots can write to sales@kiwiworkwear.com.

This is product guidance, not legal advice: confirm the ratings your site requires against your hazard assessment and local rules.