We have been retro-fitting all-metal Universals in our UK shop (Devon Harp Centre) for over 12 years, and they're sturdy and very reliable, and the one-size-fits-all is particularly useful. All-metal construction too ! Jerry's You Tube video is good, especially for beginners - he explains the installation procedures very well and in close-up detail.

My wife bought a beautiful one of a kind handmade 30-string Celtic harp more than 10 years ago, which was her first harp of that size, after she'd been playing a lap harp for a year or so. She therefore already was accustom to being able to change keys with levers. She asked me to add levers. I tried a couple kinds and found these to be the best available at the time. We hated the prospect of spending $375 (at the time) on a full set of levers (plus a lot of effort to install such that they function correctly), so we bought just enough to add one more key or two at a time. I spent about 4 years adding 4, 8 or 12 levers at a time until she finally had the full set. They work very well. Installing them does take some skill and patience, and means to verify the pitch, but I'm sure that's the case regardless of lever design. We've had these installed for many years now and she plays the harp regularly and has used the harp with these levers for many public performances. They are high quality and work equally well for her highest and lowest strings.