This bullet only has one speed and one function, which is a fast, steady, powerful vibration that is amazingly quiet (4 vrooms, 2 bees). I've never had such an easy time achieving orgasm as with this vibe. If it were much more powerful, I don't think I would even be able to handle direct stimulation from it. A sound test proved that it can't really be heard through the covers and definitely can't be heard through a closed door. That is great, since I have roommates. The O-ring around the battery compartment works wonderfully. I have washed mine under running water and taken it into the shower many times, and I have never found a hint of moisture in the battery compartment. The vibe turns on by twisting the white dial at the end of the battery cap. It can accidentally be turned off sometimes, as it turns rather easily. Birthstones runs on a single AAA battery, which lasts surprisingly long. You'll know when the battery is getting weak, as the vibrations become much louder and somewhat sporadic.