SIKA Sikaflex-221 Multi-Purpose Sealant/Adhesive, Gray, 10.1 fl. oz – Fast-Curing Polyurethane, Highly Elastic, Weather-Resistant, Sandable & Paintable, Bonds to Wood, Metal, and Plastics

Sikaflex 221 exceeded my expectations. It’s incredibly versatile, adheres to a wide range of materials, and cures to a strong, flexible seal that holds up under tough conditions. I used it for sealing my little project little tikes and it performed flawlessly—no leaks, no cracks, and it’s weather-resistant. Application was smooth and cleanup was easy. Whether you're working on automotive, construction, or DIY projects, this is a must-have product. Highly recommended!

If you need a really tough adhesive/sealant-this is it. It is a little hard to work with, but is about the best sealant I've ever used. Generally used for RV, boats, but i used it to repair the failing gasket on my refrigerator door, and it sealed it perfectly. Make sure whatever you are applying it to you intend to not take apart-it dries to very strong seal. it can be removed with a sharp utility knife or similar-but this, unlike so many of these products, is crappy water based which i generally find pretty useless for anything but gluing paper together. Even silicon-based caulks do not seal and last like this stuff. And it is equally strong indoors or out. The days of solid construction adhesive are over-except for this.

TRIED SEVERAL ON MY RV TRAILER AND THIS WORKS THE BEST FOR ME. EASY TO WORK WITH AND GOOD SEAL.

Best adhesive/sealer that I’ve ever used. I’ve used many brands of polyurethane sealant, but this one flows better and cures more flexible than other urethane sealers. I’ve used it for ceiling tiles,, shiplap,on walls, backsplashes, sealing exterior window and door frames. Holds up to weather without shrinking.

This product is not water solvable and sticky as heck. Requires a bit of caulking skill but really bonds and is somewhat sandals too.

People complaining about the wrong color or broken package is not a true reflection of the product. Amazon offers free returns, just return the wrong color and reorder.Anyways I used this for repairing a small crack in my roof flashing. Product went on easily and instantly bonded. Found it through recommendations through reddit about roof repair. It was easy to squeeze out of the tube (use a caulk gun with adjustable leverage as I had no issues at all), and was easy to spread and apply. Dried pretty quickly. Unsure about the longevity of the product but initial impressions I am very happy with it.

My new go to for waterproof sealant. UV resistant and flexible this stuff just works. It's super thick so do yourself a favor and get a decent caulking gun, your hands will thank you.

First thing I absolutely hated about this product is that it is nearly impossible to dispense it from a caulking gun without using both hands to squeeze the trigger. This makes for a messy job no matter how hard you tried not to. DO NOT get this stuff on your skin or clothing. I ruined my shirt but it was a work shirt anyway. Stains your hands black and is nearly impossible to get off even after 4 days of trying. Time will tell if it sealed up the RV window well or not.Do yourself a favor and buy something easier to use. A 10 to 15 minute job ended up taking and hour and a half to finish. Making the hole in the end of the caulk tube didn't help at all. I will not be a repeat buyer of this product.