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BASF MasterSeal NP 1 Stone Elastomeric Polyurethane Sealant 10.1 oz

Stays flexible and seals out moisture on joints that move, indoors or out.
Basf MPN NP1STN12 In Stock & Ready to Ship
$143.88
$11.99 each · sold by the case of 12 Free shipping on orders over $149
Ships within 24 hours · most orders arrive in about 2 business days
Cases of 12 · Order in multiples of 12
Ships free on orders over $149 $14.99 flat shipping until your order reaches $149.

Sold by the Case

$143.88 per case of 12

Save $21.60 on orders $75+. Spend $75 or more to unlock 15% off every case — applied automatically at checkout. Free shipping at $149.

Ships as a complete case of 12. Free shipping on orders $149 and up.

About Product Overview

MasterSeal NP 1 from BASF is a one-part elastomeric polyurethane sealant built for joints that need to move without cracking or losing their seal. Applied with a standard caulking gun, it cures to a permanently flexible bond that resists moisture and mildew, making it a solid choice for both indoor and outdoor sealing jobs around the house or jobsite. The Stone color blends into most masonry and trim, and since it's paintable, you can match it to any surface once it sets. Low VOC formulation means less odor and easier use in occupied spaces.

  • Material: Elastomeric Polyurethane
  • Color: Stone (Brown family)
  • Size: 10.1 oz. cartridge, covers up to 26
  • Moisture and mildew resistant
  • Paintable and permanently flexible
  • Indoor and outdoor use

The Details Specifications

Brand Basf
Model / MPN NP1STN12
UPC 080492302141
Weight 12 lbs
Safety Data Sheet (SDS) Manufacturer documentation · opens in new tab
Price check

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On Amazon, start with these four questions before you click buy.

01

Who's actually selling it

The brand name is on the listing. A different company is in the seller field. Those aren't the same thing, and the second one is who you're buying from.

02

Whether the warranty survives

Most manufacturers only honor a warranty when the unit came through an authorized dealer. We're authorized for Basf. A third-party marketplace seller usually isn't.

03

Where the box came from

Gray-market stock, returns repackaged as new, and outright fakes move through marketplaces constantly. It all looks identical in the photo. It stops looking identical when it fails.

04

Who you call when it breaks

Ours is a phone number with a person behind it who has held this product. M–F, 6 AM – 5 PM Pacific. (866) 469-8556

The big boxes don't care if your hardware store survives.

Amazon, Home Depot, and Lowe's are built to pull every hardware dollar out of your town. When the local shop can't keep the lights on, the counter where somebody actually knew which part you needed goes with it. We're built the other way: real brands so you're never stuck on a marketplace, and a straight answer to buy it down the street when that's the better call. Support independent hardware — it doesn't restock itself.

Why we tell you to shop local
Authorized dealer · Basf

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