The external pink sleeve actually comes off the main bullet vibrator unit, to provide a smooth black/dark grey vibrator with an ABS plastic feel rather than silicone. This means the vibrations are felt more directly on the body, making it much more intense. The sleeve is quite fiddly to take off, especially if you're worried about breaking your nails. Also, resting the vibe any which way to try and remove the sleeve means you accidentally turn the thing on. A LOT.