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.

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!

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.

I bought this sealant to help seal the slide-out of my travel trailer. I used a caulk gun to apply the sealant to the trailer once I had prepped all the surfaces. The sealant goes on very easily. Although it can be a little sticky at times. I used soapy water and some kitchen roll for cases where I applied too much or got it on my hands. In the first 5-10 min it will easily come off if you make any mistakes in applying it. I have had it on my trailer for a few months, and I am really impressed on how it stands up in the weather. Our trailer sits out in the full sunshine for most of the time, and the sealant holds up very well. The only "negative" is that the curing time is about 24 hours not 30 minutes if you apply it in large quantities or in a large area like I did.

I needed it to seal some great light units on a car as condensation was getting in. The seal was visible so i had to be sure to do a neat job so it didn’t look botched. I used masking tape to get a straight line. The sealant seems very soft which is great to apply and then smooth it to the finish that you want. Within a few hours it goes rigid and is a Matt ish appearance. Ideal for the job. You can tell it’s serious stuff when you try to get it off your fingers but kitchen detergent did it fine. A great product and pleased I chose it out of all the others available

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

I used this product as instructed. The seller said it would dry in 30 to 60 minutes, but the opposite happened. I waited 12 hours and it still didn't dry. Bad experience.

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