The functions of this bullet pack are very simple and easy to use. There are two buttons on the batter pack. One is labeled On/Off and the other is labeled 7X. To turn the power on or off press the On/Off button. The bullet will turn on in a high steady vibration. To move to another vibration pattern, press the 7X button. The patterns include the following: strong steady vibration, strong fast pulses, strong pulses followed by 10 seconds of a medium strong steady vibration and then 10 seconds of a strong steady vibrations, slow long pulses followed by short fast pulses, alternating strength steady vibration, short fast pulses followed by gradually longer pulses, and short pulses followed by long steady vibration. All of the vibrations are extremely strong and buzzy. The vibrations are strong enough that when turned on and laid in the palm of my hand, the bullet moves itself across my palm. After about 10 minutes, the bullet starts to warm up, but it didn't become alarmingly hot at any time. The noise level is noticeable with this vibrator but it probably can't be heard through a door or over the shower. There were no noticeable problems after exposing this to water.