A look inside a Darsonval style modern Violet Wand Ray unit.04:33

In the dawn of the electrical industry the new wondrous electrical energy was presented as a cure for all ailments. There were a wide variety of electro-healing machines being sold, and some of the most stylish are the slightly scary violet ray and violet wand units.
These devices traditionally used an electromagnetic interrupter to drive a high voltage air-cored step-up transformer. The output was applied via glass tubes with a vacuum pulled on them so that they glowed purple as the high voltage electricity coupled through the gasses of the rarefied air inside. The units made a loud buzzing crackling noise and when the glass electrodes were applied to the body, showers of fine fizzing sparks would crackle to the skin accompanied by a strong glow from the tube and a smell of ozone.
These days they are still manufactured and used for completely different reasons. In the “beauty” industry they are claimed to purify, detoxify and rejuvenate skin while stimulating bloodflow. Pretty much the same crap the medical quacks came out with in the beginning. The other major market is electro-fetishism where the scary and tingly effects are popular for kinky fun.
The original units sometimes came with an optional metal rod that could be inserted into the end of the wand to allow the user to hold the output of the coil directly and then apply sparks to the patient from their other hand. These metal rods almost always have a direct electrical path to the mains supply and I strongly recommend they are not used as the only thing between the person holding the rod and a very violent death is luck. Holding the rod in one hand and making contact with a grounded object with another part of the body can result in significant mains current flow depending on how the unit is wired. The traditional glass electrodes couple the output to the recipient with two layers of glass and a conductive vacuum or noble gas and provide good isolation between the output and mains ground.
The modern Chinese units are sold as Darsonval (d’Arsonval) units. A name that indicates the effect of high frequency current passing over a body without causing muscular contraction or sensation. they usually come with a choice of neon or argon filled electrodes that glow orange and purple respectively. The modern ones use a traditional style of coil, but made with modern materials and driven by electronic circuitry instead of a magnetic interrupter.
Note that these devices give off a very high voltage gradient that could cause serious damage to electronic equipment in the vicinity, so they should be kept away from sensitive components and devices. They can also create electrical noise and mains borne transients that can push old and failing wiring over the edge. So use with care if at all.