Review on 🎛️ Oznium Mini LED Dimmer Knob with Rotary Control Switch - PWM Dimming for 12-24V LEDs, Fully Waterproof, Dimming Up to 4.8A at 12V or 2.4A at 24V: Car, Automotive, Marine, Low Voltage Under Cabinet Lights by Jason Cartwright

Seems to work well, but they're pretty cheaply made, especially at $24.99. So I would say they are overpriced. I ordered three of these and the first one I installed broke right after installation. To actually mount the dimmer behind the surface, you need to remove the decorative knob to insert it into the hole you drilled. The knobs are easily removable and the stem (i.e. the actual dimmer control) is all plastic, including the threaded part you attach it to. After installing it and locking it in place with the locknut, I proceeded to reassemble the grip onto the stem. With the effort to push the handle back, the handle simply snapped off the plastic threads. If that part was metal or solid, or the handle didn't require that much effort, it would probably be fine. I think the pressure of trying to put the knob back onto the stem caused it to fail at the joint where the threaded part is held by the nut. The dimmer still worked but the filaments were broken and the dimmer box didn't connect and there was no real way to reattach it. Try to put the decorative handle back in for fear of breaking the second one.