The Smartballs Teneo Duo by Fun Factory are a set of Vaginal balls that are used for increasing your PC muscle strength and vaginal tone. What they do is they stimulate the muscles to contract around the balls the same way that doing kegals would do. The balls are weighted so that you must squeeze around them to keep them in, so it is like having a set of barbells for those muscles.

The Duo are two balls that are attached to one another, each of the balls contain a smaller weighted ball that moves in side and vibrates when you move. These vibrations stimulate the muscles and cause them to contract.

The balls are meant for Vaginal Use only and so are really only for those who have a vagina. Even though these have a retrieval string, do not use them anally. They are far too small and could easily get lost inside of the body.

The Duo have an inner ball that is made of plastic that is wrapped in an outer silicone ball. The material is 100% body safe, latex free, and pthalates free. While there are some ridges along the balls, I did not find that the texture really did much during use other then it made a little easier to grip when I was inserting or removing the balls.

The Duo balls are shaped like small eggs, with silicone wrapped around them and are connected to one another via said silicone. The second of the balls has a retrieval cord that is attached and a slight dip in the bottom to help with insertion so you can press it in with your finger tip. It is easy to feel the balls when you hold it in your hand, shaking and slightly clacking inside of the outer ball.

Measurements

Total Length: 7 1/4"
Ball Length: 1 3/4"
Ball Diameter: 1 1/2"
Middle string length: 1/2"
Retrieval Cord: 3 1/2"

Because they are made of Silicone you do not want to use silicone lube with these toy for insertion. I recommend water based lubrication only as it won't degrade the material

Storage is simple, you can choose to leave them in the box that they came in or they will easily fit in any storage bag, box or drawer.

As for how these worked, I think I am personally going to be sticking to my Uno for a little while longer. I thought because I was turning 30 and that the Duo was recommended for those who are 30+ or who have had children that I might need them, but I found them to still be a little too much for me in size it almost feels too full and I am not able to keep them in for as long as I would my Uno.

I still believe that they where very stimulating and did work, but other factors kept them from being amazing for me.