The Yooo is a uniquely shaped vibrator, featuring two vibrating balls. When I first saw it, I hoped I would be able to use it with one ball on either side of my clit, similar to the Form 2. It turned out to be much bigger than I had originally imagined. For me, the Yooo works very well as a dual stimulator, with one ball against my clit and one inserted for shallow vaginal stimulation. Since we are all built differently, not everyone will be able to use it in that way. Those who can't could use it for clitoral stimulation, with the other ball resting against the labia or edge of the vaginal opening (although depending on your preferences you might find that the other ball doesn't add much or just gets in the way). Males could use the Yooo's balls against their own, or place their penis in the dip between the balls and slide it up and down the shaft. It also works well as a body massager; the soft, round balls feel much nicer on sore muscles than most vibrators would.

The Yooo is made from silicone, so it's non-porous and body safe. It had a slight smell when I took it out of the box, which must have come from the packaging or the manufacturing process, since silicone itself has no odour. The smell disappeared after a quick wash. The silicone has a matte surface that provides some drag. Unlike most of my silicone vibrators, it has a fairly thick layer of silicone covering the motors, which provides a good amount of give. There is a small seam running around the middle that can be felt with my fingers, but I've never noticed it during use.

The Yooo is made up of 3 balls of varying sizes. The central ball houses the controls and fits nicely into the palm of my hand. On either side of it are balls which measure 1 3/4 and 1 1/2 inches wide. They each contain a vibrating motor. The distance from the edge of one ball to the middle of the other ball is about 1 1/2 inches, so dual stimulation will work best for those whose clits are between 1 1/4 and 1 3/4 inches from their vaginal openings. My clit is about 1 3/4 inches away (yes, I measured!) and I was able to insert either ball with the other resting against my clit. The 1 1/2 inch ball works nicely as a warm up for me, and the 1 3/4 inch gives me a very full feeling. If you like deep penetration this obviously won't be a good toy for you, but if you prefer girth over length it could be a great choice. It is much more compact and easy to hide or travel with than a traditional rabbit vibrator. The design is fun, futuristic, and discreet and it comes in some great colours.

Vibrations
The Yooo's vibrations are very rumbly, to the point that some of the steady settings almost feel like fast pulsations. It can't compare to something with a power cord, but it's one of the more powerful toys in my collection. It's not quite as strong as my Form 2, We-vibe Touch, or MiMi, but it's a little stronger than Siri or Spring, a good bit stronger than bCurious, and about the same as Form 4. The Yooo's vibrations feel like they have a wider range of motion, and move back and forth more than any of the toys I listed. The vibrations are a little louder than I'd like, and can be faintly heard through my bedroom door. Music or the sound of a shower can easily drown them out. As I mentioned earlier, the motors are located in each of the outer balls. The center ball helps to buffer them the vibrations, but they can still be felt pretty strongly while holding it.

Controls and Settings
The buttons (and the symbols on them) are raised, which makes it easy to find the right one without looking at them. They require a little bit of force to press, so they won't get bumped accidentally. The buttons and a raised line around them light up when they are pressed. They also sometimes light up when I touch the control area without pressing a button. Fun Factory calls this "Magic Touch" and says that "with a touch of the control unit, the switched off toy lights up, signalizing it's ready to go." The lights don't turn on every time I try to activate them. They seem to light up about 50% of the time when I hold my finger over the metal logo in the center of the control panel. I don't really see the point in this feature. I guess it could be used to check whether the battery is dead or not, but I can just press the button and see if it will turn on, and that works 100% of the time.

The Yooo has 3 buttons: (+), (-), and (*). The (+) button turns the vibrations on, and increases their intensity. There are 8 levels of steady vibrations. Once you reach level 8, pressing the (+) again will cycle through the patterns. The (-) button will take you back to steady vibrations, decrease their intensity, and can be held to turn the toy off. The (*) button is used to turn on Turbo Boost. Basically, it's the 9th level of vibration, but somebody decided it would seem cooler if it had it's own button. Tapping the (*) will give you a little spurt of extra power, and if you hold it down for a second the toy will remain in Turbo Boost mode until you press it again. It's kind of convenient to have a quick way to jump to the highest level (which I always use) without having to scroll through all the others. The lights flash the entire time the toy is on Turbo Boost, which can get annoying.

Since it is waterproof and non-porous, the Yooo is easy to keep clean. It can be washed with toy cleaner or soap and water, or sterilized with a 10% bleach solution. Silicone lube can damage silicone toys, so either make sure to perform a spot test, or stick with a water or oil based lube to be on the safe side.

Charging
The Yooo uses Fun Factory's Click 'N' Charge system. Instead of having a charging port, the charger magnetically attaches to a contact on the top of the toy. This means that there are no openings in the toy, and it is completely waterproof. The only downside is that if the toy gets bumped, the charger will move out of the right position and stop charging until you fix it. There is a red light on the charging cord that glows when everything is lined up properly and the toy is charging. The white lights on the toy also slowly pulsate at different times. When it's fully charged and ready to go, the red light turns off and the white lights start to flash faster and simultaneously.

You should charge the Yooo for 6 hours before the first use. I found that each subsequent charge also took about 6 hours. The battery life depends on the setting you use, but on Turbo Boost it will last for about 30 minutes. That's a longer charge time and shorter run time than any of my other rechargeable toys, but it lasts long enough to get me through a session. I leave it to charge after every use so I don't have to worry about it dying in the middle of the fun. The long charge time and relatively short run time will be a problem for those who would like to use the toy for long sessions, or use it again less than 6 hours after their last use.

The charger has Fun Factory's logo and slogan ("love yourself!") on it, so you may not want to leave it lying around after you put your Yooo away.

The battery can't be overcharged, and doesn't have a "memory," but the toy shouldn't be stored with the battery completely drained.

The packaging is attractive and looks high-quality, but doesn't work well as storage. The Yooo comes in a small grey and red cardboard box. The front is cut out, and the Yooo is visible behind a layer of molded plastic. The back and sides have pictures and features of the toy. The instructions are detailed and informative, and available in several languages. There is also a pamphlet showing all of Fun Factory's products, and a sample packet of their Toyfluid water based lube. The charger comes packaged in it's own box, with it's own set of instructions, which is a repeat of the charging information given in the Yooo's instructions.