I got one of these when I purchased a Leopold keyboard from Korea. The
JSCO mice are claimed to have tactile feedback without the clicky sound, like a Cherry Brown.
Most of the JSCO mice are a bit small. The JNL-006K is a new model that is more the size of mice in the West; maximum body dimensions are 116x58x36mm. Construction is noticeably lighter than my Logitech mouse, but it doesn't feel flimsy or creak.
As for the button action, it feels and sounds like a very short travel membrane switch. It is plainly audible in a silent room, but is much quieter than a normal mouse. The scroll wheel is notched but is also very quiet.
After I tried it a while, I thought it was a bit too light for me to prefer it over my old Logitech. But going back, I find I'm now irritated by the louder clicking.
Considering the retail price in Korea is <$10, I think it's a good buy.
