XFasten Silicone Sealant Waterproof Black Cartridge, 10.1 oz (4-Pack) Black Caulking Silicone Adhesive Sealant Cartridge for RV, General Use, Window, Door, Glass, Automotive Leak Sealing

I want to address some of the negative comments. Please be aware of what you’re buying, and make sure you understand what you’re talking about before leaving a review. This product is an industrial-grade silicone sealant, meaning it’s designed for professional or specialized use. While it may look similar to the silicones sold at retail stores, its curing chemistry, adhesion strength, and environmental resistance are on a different level. Secondly, any product labeled “marine” or “aquarium” grade is designed with different performance characteristics and curing behaviors. These formulations are typically made to resist long-term water exposure and maintain adhesion in wet or submerged conditions, which sets them apart from general-purpose silicones. Now, regarding the chemistry — this is a neutral-cure silicone. Neutral-cure silicones release alcohols or oximes instead of acetic acid as they cure. Because of that, they tend to be more sensitive to environmental factors during curing, including temperature, humidity, surface contamination (like oils, grease, or dust), and material compatibility. While “more sensitive” is true to an extent, they’re also generally safer for metal and masonry surfaces compared to acetoxy (acid-cure) silicones, which can corrode certain materials. With that in mind, this product offers excellent value and performs exactly as described — if you follow the instructions and surface preparation guidelines carefully. I have no doubt that it can meet or even exceed its 15-year durability rating when properly applied and cured under suitable conditions. Lastly, this is not a glue. It is not marketed or intended to be one. It’s a sealant, designed to create a flexible, watertight, and weather-resistant seal — and it performs that function exactly as it should.

Great seal ability and durable. Works great as a sealer and an adhesive. Highly recommend this product!

saved $500 installing the windows myself and this was my choice of caulking. i bought 2 tubes but needed 4, so i ran to home depot and got 2 more. the home depot ones are garbage, when i removed the shims, the windows fell down the next day, where as the amazon caulking was amazing a held the other 2 windows in. hard to believe, but it's true.

It's OK, but it dries FAST. I used masking tape along the borders and after 3 minutes i tried to remove it but a thin film had already hardened on the silicone and removing the tape messed the initial smooth surface up. Too bad. This is not the first time I have worked with silicone. Just be warned, that's all.

Installed a new black sink in my kitchen and it worked out perfect . Good seal , dried well and easy clean up . Easy to use . Follow instructions . Highly recommend !!

Performs as expected.

Works so well with dark stone like marble. It comes out easy and dries super nice. I’m so glad I was able to locate black!

did a good job covering the spots I needed caulked but was impossible to deal with after the first use. It was virtually impossible to get out of the tube in spite of it being stored properly after the first use.

As described, good product,

Very dirty product , probably mixed with printer powder , the black spots were all over and hard to apply and clean

This is a lovely matt sealant which could be used on joins on black granite e.g worktops. We used it after painting 1930s Crittall windows (Matt paint) to seal any gaps between the window frame and the sill. So good it can’t be seen and easy to use. Dries quickly.

Expensive for what it is

Easy to apply silicone works well