Tubeless explained

Tubeless tires are tires that do not require an additional inner tube. The tire seals directly to the rim, and a tubeless valve is installed into the rim hole.

In cycle tires, there is a “UST” system that works with completely airtight tires, and a "tubeless ready" system that uses thinner and lighter tires, where a small amount of sealant has to be filled into the tire to seal the tire and gaps between tire and the rim.

The reduced weight and the additional puncture prevention provided by the sealant has led “tubeless ready” systems to become the prevailing technology. Most MTB tires and rims sold today are tubeless ready and the user can convert to “tubeless ready” by removing the inner tube and adding the tubeless valve and sealant.

The advantages of “tubeless ready” systems are

The disadvantage of tubeless systems is that the sealant has to be filled into the tire during installation, and a regular check of the sealant level is necessary because the sealant gets old and dries up over time.

The additional complexity of installation and maintenance of tubeless systems has kept many users from converting their systems to tubeless. That’s why milKit was invented: to make tubeless systems easy!

More detailed information on tubeless technology can be found here