I received this little surprise gadjet today! thank you and yes the black box of the musician!
as was said before tuning the technology used is not very common ... but after a test, it works perfectly! on the other hand in the notice of gromeul, is said to be the reflection of two LED are aligned, then they should just stop moving. jlai not tried it yet away from home so I can not really invent its portability ... but this thing must weigh 20gr everything peter! and the size of a pick holder (what sticks to the body of the guitar). no info su rla life of the battery in the manual, but the lithium button batteries normally last very long. I do not know if I made the purchase of this tuner because I was free! yay!

ps: I regret the absence of a stripped down version
pps: in fact down version exists