I've got 2 of them & they both work well. I'm happy with mine BUT other members have had issues though:
- some units not working properly straight out of the box. Not much quality control on the eBay ones?
- they appear to break/fault fairly easily if dropped etc.
- the clip is pretty weak so don't count on it to hold in place on anything I.e. harness, belt, detector cover - see 2nd point. I use velcro to hold mine in place + the clip. Hasn't come off yet.