I wish the manufacturer had some more info on it. Seems to be some adjustments with the included allen wrench, but not sure how close to get to the strings with the pickup. Price was very good for what you get - under $50 after shipping IIRC.
Grizzly has it in their system as H 6055.
Box says Samba S4021 made in Korea
It installed very easily, no mods are needed. I have 2 flattop guitars, and 1 acoustic/electric bass, and I wanted a pickup that could easily be moved to any of them.
Where Obtained: Grizzly
I have it in a Sigma acoustic guitar. It has tone and volume controls. It is single coil, but very quiet, hum is very very low.
It is very quiet, quieter than most single coils. Has a metal plate on the back, which must be helping. I was really glad that its quiet. Tone is pretty good, but this is my first sound hole pickup. I have only used it with a small SS Fender amp so far.
It seems to be well made. The cable leading from the tone/vol control box is detachable, so if it failed you could make your own cable for it and replace it. The tone/vol control box could also be easily bypassed and you could wire the pickup to a jack or another EQ/vol depending on your needs.