I have them on several basses; they work.
When tuning you do have to operate a couple of times back and forth to cover off string slackening/tightening variations.
The dropped position has a small thumb-screw adjuster.
There are like-for-like models for most common bass tuners (they discontinued the Ric ones, though).
They are drop-in replacements for the stock tuners, but you do have to use their countersunk screws rather than the original raised-dome ones (they need to be flush-fitting for the clearance of the moving part over the base plate).
When choosing, they do gold/nickel/chrome/black finishes.
BTN & Allparts sell them in the UK.