There are currently 2 versions of the Ring Kit (beta) available, the “core” and the “long”, (full disclosure, I only purchased the long so any mention about the core is assumption). The Ring Kit comes with the sleeve, 9 rings, and the hard black plastic storage case. The sleeve is similar to the Gen2 in size and has about the same thinner walls to accomodate stretch much better than the thicker sleeves like the lips. The inside texture in the bottom half is slightly different than the Gen2 but in use feels very similar. A main difference is in the 3 grooves where the rings are designed to go. There is one groove at the base opening and 2 in the top 1/3. At those grooves there is a small rounded texture molded into the inside of the sleeve with a few small bumps on it so there’s slight increase in pressure at those spots even without a ring installed.
The 9 rings are divided into 3 sets differentiated by color. Each color has one of each different size, approximately 1" (25mm), 1 1/4" (32mm), and 1 1/2" (38mm) inside diameter. The rings are made of a stretchy material much like a stiff rubber band. They are designed to be placed in the grooves on the sleeve to adjust the size and amount of restriction at that point of the sleeve.
So, how does this all come together? The sleeve alone is sure to be accepted because it’s similar to their best selling sleeve, the Gen2, and currently less expensive. The rings add another dimension because they allow the user to adjust the diameter of the sleeve to better accomodate different girths and preferences in tightness.
The Long sleeve is approximately 3/8" (1cm) longer than the Gen2 (which I assume is the same length as the core). There are some who will find that additional length welcome but that may come with a problem. The stretchy walls of this sleeve allow it to stretch in length too so if you place a restriction (ring) on the sleeve it stretches the sleeve as the glans tries to pass through. To effectively use both of the upper grooves I would estimate you would need to be about 7.5" (190mm) + in length to accomodate that stretch and have your glans fully pass through. This of course depends on girth and tightness of the ring. I’m above average length and girth and wish I had bought the core.
Another annoying problem, who decided to not separate the ring size by color? Each color set has one L, M, S ring instead of each color set being a different size (note to marketing, you already introduced many of us to color=size with the Mod sleeves and then you used those same colors for the rings). If you want to change ring size you need to guess or remember what size is on the sleeve, could be any color, and then fish around by size to find the next larger or smaller. It would have made more sense, to me, to have each color set a different size. Current pictures on the website also do not make this clear.
Final thoughts: It’s a good sleeve and a good first attempt at a “one size fits all” solution. The core will most likely have a following and the long should appeal to those with a lot of additional personal length.