The Yooo is part of Fun Factory's Click 'n' Charge line of toys. This one was designed for external stimulation. It offers dual motors, one in each ball, for a different kind of experience. There are no real limitations to this toy that make it best for a specific type of user, so it can be enjoyed by everyone. I really like the fun colors that Fun Factory uses for their toys. I got this one in the green and it is nice and bright and a great addition to my mainly pink and purple collection.

Yooo's body is made from silicone and the area made for controlling the vibrations is made from plastic. The silicone is 100% silicone and has no real smell or taste. It is phthalates free, hypoallergenic, and non-porous. It has some give and a little bit of drag, but not too much. If you want to be able to easily glide it over the area of your choice I suggest lube. You should only use water-based lubricants because silicone lubes can damage the toy.
This toy is also fully waterproof, so cleaning is easier because you don't have to worry about water getting where it isn't supposed to be. Warm water and soap or toy cleaner will get the job done perfectly. If you need to sterilize it, your only option is to wipe it down with a 10% bleach solution as boiling will ruin the motor.

The shape of Yooo is interesting. It reminds me of Mickey Mouse ears, with one of the ears being a bit smaller than the other. One of the balls is about 1.5 inches in diameter and the other is larger at 1.75 inches in diameter. There is a space between the balls, so depending on your anatomy you can stimulate two areas at once or two sides of an area. Finding a position that works best for you can take a little while. For example whether you want the bigger ball or smaller ball to be in a certain spot or if you only want one ball stimulating you. Also, depending on what area you are using the Yooo on it might be hard to get a good grip on it. All of these issues I had with the shape only occurred for the first couple of uses because I just needed to get used to this different shape. After I was used to it I was able to really make it work for me.

To turn Yooo on, you hold down the + button for a few seconds. This will start you on the lowest level of vibration. Even though there are 2 motors, they are both controlled together. To increase the intensity, simply continue to hit the + button and if you need to decrease intensity hit the - button. The buttons do take some force to push down enough, this is a good thing because you won't accidentally hit something. However, it is an issue when you are in the heat of the moment and want to change the speed because it requires enough force that I get distracted sometimes.
There are a total of 8 different levels of steady vibration. The vibrations are pretty rumbly and strong, which is nice and to me they feel a little different in the two balls. The smaller ball seems to be better for pinpoint stimulation and it feels a bit stronger at times. The larger ball works better for broad stimulation and the vibrations sometimes feel a bit weaker here (maybe it is because they are more spread out). One thing about the vibrations on higher levels is that they feel like they are pulsing. At first I thought there were only a few speeds and then patterns started after a few pushes, however I was wrong. I have read this in another review as well, so I know that mine is not defective. If you need an extra boost of power, you can hit the * button, which is the boost button, and this gives you the highest level of steady vibration.
After you go through the steady speeds, there are 4 patterns. The first 3 are similar because they are escalating/roller coaster type patterns that go back and forth between the two balls. The last pattern is a pulsing pattern.

To charge the Yooo, you need to connect the magnetic charger to the Fun Factory logo on the toy. When it is properly connected it will glow red, if it is not glowing then it is not connected and therefore it is not charging. Since this is my second toy with this system I didn't have as much trouble as I did the first time getting it to stay so that it can charge. It takes about 6 hours for the initial charge and it can sometimes take just as long to fully charge it if you let it run out all the way. I wish it didn't take so long to charge. It will last for a little over 30 minutes on the highest setting, but longer if you are using lower settings. Mine tends to work for about 4-5 days of use before it needs to be charged again.

Aside from it taking me a few tries to find the best way to position this to get the best stimulation, I have really enjoyed the Yooo. My anatomy allows me to rest one of the balls on my clit and have the other one right outside my vaginal opening. This feels really good! I also have no trouble applying pressure to the area when I want to. The vibrations are plenty strong enough for me (even without the boost button) and I like using this one for warm up and for days when I only want a clitoral orgasm. I can get some pinpoint stimulation, but not as much as I would like sometimes. Yooo also feels good on my nipples and my neck. If you want to use Yooo with another toy vaginally, you might have some issues getting everything positioned because one of the balls can get in the way.