This is a standard tuner.

The Korg Ca30 Compact Chromatic Tuner is what I have always come back to during my 8 year wind playing career.  This is the tuner that is the standard for almost all high school musicians, and with good reason.

Firstly, it is fast.  It almost follows your adjustments to pitch in real time, with a delay of perhaps a 2 milliseconds, but not enough to really be noticeable.  You could spend less money, but you will be hard pressed to find a tuner that is this fast for a lower price, or the same price.

Secondly, it is accurate.  The Korg identifies pitch to withing 5 percent, in all cases, in all registers, for all wind instruments.  The only time I've had a problem with its accuracy is when I'm in a large group rehearsal (I haven't found a tuner yet that can deal with that without microphone aid) or when the battery is low (a problem for all tuners.)

I have also noticed that the battery life is exceptional with these tuners.  I have to switch out the battery about once per year, and that is very comforting to know, because a good musician is using a tuner constantly.

I also has an adjustable standard.  This means that if you run into a situation where you need to tune to something other than 440 (like if you move to Europe or something silly like that), you can.  I like to use that feature just to see how far I can push my ability to adjust.  I'll tune my horn to 440, then reset the standard, and see if I can still make the light turn green on every note.

There are no complaints for this tuner, and all other 'better' tuners merely improve upon the foundation set by this exact tuner.  But those are more expensive, and usually you do not get the necessary bang for your buck with those.  The Korg has everything anyone would need, and everything else is extra.