The instruction booklet says that installation is a job for a luthier. Actually, it can be done on your own if you have time, patience and some skills, but don't underestimate the time and the courage needed to drill a 12-mm hole in your precious instrument.
After the installation, the visual result is excellent - you just see a high-quality metal endpin. I found also the sound excellent; before installation, I had experimented with a cheaper external sensor and the difference is striking. This K&K provides a high-quality output signal which is pleasant and natural when amplified, and is very good also for recording.
The package includes a very simple metal tool designed for installing the sensors in an f-hole mandolin. For my oval-hole mandolin it was useless, and actually, considering the price, they could have provided a better tool capable of reaching deeper into the instrument. This is my only negative remark.
After some experiments, I installed the sensors not on the soundboard, but on the back of the instruments (the part which touches your belly). I am very happy with the result because the level of the output signal is still very good and the pick noise is greatly reduced, but of course this depends on the instrument.
