It's unusual to find NOS (New Old Stock) ionisers, and when I bought this random one on ebay I didn't even know it was new or even what brand it was. It turns out it's an early Dezac Breathe Easy ioniser and the lack of a plug suggests it's pretty old.
I was actually quite excited until I opened it, since I don't think I'd seen this particular model of ioniser before. Then that excitement turned to disappointment when I opened it and realised it was an older version of what I regard as one of the worst ioniser designs ever produced.
The circuitry is all absolutely fine, but the layout on the PCB seems to have been done with misguided economy in mind and as a result the high voltage end of the voltage multiplier is brought straight back to the low voltage end with spacing that alludes to a complete misunderstanding of the characteristics of high voltage ionisation.
The current involved in ionisation is very low so any leakage either by direct tracking or local ionisation is critical. These ionisers probably worked for a while, but would gradually stop working due to internal tracking.
I had a dig around and found another version of this design with a more modern case that had been in use for some time, and the internal effects of the poor spacing are very visible.