The vacuums are bottle-shaped crystals with metal-like appearance. The designs and colors are varied. But in general, the crystals often divided into two or three parts. The first part acts like the cap of the bottle. The rest acts like the body of the bottle. There are thin parts that act like connectors connect the parts of the bottle. There is also a swirl design that wraps around the crystal.
In the episode "Friends in Need", the Trix summoned them at Alfea because Icy felt that the Dragon's Flame was somewhere in the school. Unbeknownst to the Trix it was following Bloom as the flame resides in her. Fortunately for the Winx and Specialists, it was at a distance. Eventually, it ended up in Faragonda's room. As Bloom and the others were hiding in order to corner the Trix and confront them on their presences at Alfea. Faragonda turned on the lights before any answers were given and questioned their presences in her office instead.