This is a vaginal muscle exerciser, meant to remind users (when they're wearing it, of course) to do their kegels. Even when the wearer is not paying attention, she will be strengthening her PC muscles. The way this works is... Well, you unconsciously use your muscles to hold the ball in place. There is a marble (or something similar) inside of the Teneo Uno that rolls and bounces around as you move throughout the day. This causes a slight slipping sensation, which causes extra tightening and flexing of the muscles.
I believe that the single ball is an easier introduction to this type of exercise product than the double ball, and would also be a better fit for women who have a tighter or smaller vaginal canal.

The packaging has the following text about the exerciser:
>>Smartballs Teneo Uno<<
A unique pleasure!
>>Smartballs teneo uno<< Captivate lovers of the smaller pleasures in life. This vaginal ball is especially suitable for beginners and for women with a dropped or tilted uterus or those who simply want to get their pelvic muscles back in shape. Trained muscles lead to more feeling during sex. The ergonomically formed finger hollow "easy-in" makes insertion simple. The innovative technology promises extremely quiet and smooth use as well as a very stead and fast rotation of the internal ball. Midwife Christine Niersmann on FunFactory Smartballs: "Training with SMARTBALLS is super easy and effective. During everyday movements the balls train the sensibility of the inner musculature, activating the muscles and strengthening the pelvic floor."

Note: This product is ONLY meant to be used vaginally.

This product is made of silicone (a 10 on the material safety scale) with little bits of ABS plastic (an 8 on the material safety scale) showing through. To clarify, for the turquoise/white set, the turquoise area is silicone and the white bit showing through is plastic. Because the Teneo Uno is composed of these materials, it can boast safety features such as Food-grade material, Hypo-allergenic, Latex free, Non-porous, and Phthalates free. This product is waterproof, hands free, and comes with a small packet of lubricant, just in case you need it. The lubricant is water based, so it can be used with any toy your heart desires, and is safe to use with condoms as well. It's also odorless and easy to wash off- just soap and water! This product does have silicone ribbing in some areas (will be explained/described below).

The Teneo Uno, has an interesting design. It looks sort of like a plastic ball wrapped in strips of a different colored silicone. There are ridges where the silicone appears to be double layered, and places where the plastic shows through. Oddly, this gives the Teneo Uno a somewhat sporty look. That's the only word I can think of to describe it. The ball portion of this product is round, but somewhat oblong. Only slightly, though. From the top of the ball to the tip of the removal loop, the Teneo Uno measures 5". The insertable ball is 1.75" long and 1.5" wide (4.75" in circumference)

I'm going to admit right here and now that I am a total newbie to vaginal balls and exercisers. To be completely honest, I was (and still am) a bit unsure as to what I should feel or expect. That being said, I find this product to work rather nicely. I think it's somewhat large, but other reviewers have said that its smaller than other vaginal exercisers. Either way, it inserts easily and rests within the vaginal canal comfortably. The Teneo Uno isn't highly stimulating. If anything, it's pretty easy to forget about while you're wearing it. The removal chord does take some getting used to, but after that... I know this is an odd comparison, but it's similar to a tampon. You insert it, kind of wiggle around for a minute in an effort to adjust to the invader, and then eventually forget about it. Like I said, it's not highly stimulating, but I did notice a slight increase in vaginal lubrication as I wore the exerciser, and I also noted feeling a bit of a "full" feeling. Another thing I've noticed is I pee a lot more frequently when wearing this exerciser. I guess it presses against the bladder or something. As you go about your daily routine, there will be times that you can barely feel it, and other times that it's stimulating enough that it causes a little tingle in your nether regions and a flutter in your chest. After wearing this exerciser for a while, I did notice that kegels were becoming easier. I'm wondering already if it's time to move on to the Teneo Duo set!

Because this product is composed of mostly silicone, it should ONLY be used with water based lubricants.
To clean, it can be boiled for 3 minutes, washed in the dishwasher (top rack), or simply washed with soap (or toy cleaner) and water. One thing to watch out for is discharge or soap stuck in the ridges and crevices of the toy. It's not SUPER likely to happen, but there is a chance. It's best to just check, for hygienic safety.

Something I'd like to point out:
I've heard several complaints (not about this product, but others of this material) that the silicone melts when stored with other toys. I get the impression you want to store each toy (silicone or otherwise) in separate pouches or boxes in order to avoid contact that may lead to melting.

The Teneo Uno comes in a relatively low-key cardboard and plastic packaging. The cardboard is a matte red and silvery-gray color scheme, and nothing about it screams sex. There is an outline of the product on the front of the box, as well as a viewing window through which you can see the actual product within the plastic casing. On the right side panel of the box, there are a few diagrams about the toy (where it goes, that it's waterproof, what it's made of, and that it has an easy-insert finger dimple in the bottom). On the left side panel, there is a little information about the company itself. The back panel is composed of 2 flaps that are held closed by magnets. When you open the top flap (the right side) you find text in multiple languages about the product itself. Upon opening the second flap (the left side) you find a numbered diagram of the product, with each number explained below.
1. Flexible removal band of silicone
2. Finger hollow "easy-in" to assist with insertion
3. Velvet matte structured silicone surface
4. Perpendicular stripes for better sensitivity
5. Body compatible and easy to clean material
6. Odorless
7. Extremely quiet and smooth

Apparently Teneo, in Latin, means "to hold or keep".

I noticed a couple things while wearing it:
One thing I noticed about this product is that it made me have to pee nearly twice as often as I usually do. I'm not sure why this was, but I'm thinking maybe the location of the ball interferes with the expansion of my bladder? Also, while wearing it, I noticed that I felt a bit crampy, sort of like I feel when I'm having a menstrual cycle. I can't even think of a possible explanation for that. Removal can be a bit tricky, especially after you've been wearing it all day. Your muscles sort of clamp down likes "No! It's mine!" when you try to pull it out, but the removal loop is relatively sturdy, so you will eventually win.