An electrically powered light source including a light emitting diode having variable chromaticity, which is adapted for use in a dental operatory. In one embodiment, for example, a system monitors parameters or values generated before, during, andor after the course of a treatment. The fluid outlet is located between two rolling cones, but is positioned closer to one of the cones than the other. The second portion has a higher tactility than the first portion so that the user of the glove may more easily feel through the second portion than through the first portion. The retry request includes an overhead bandwidth factor.