Harley Benton CPT-20

Good:-
This is a cheap and cheerful A440Hz [not adjustable] tuner with proper bypass.
Nice and quick to react, and makes it clear when a string's in tune.
Copes with Drop A on guitar, and B on a 5 string bass if it's first in chain, and happier with bridge pickup signals.
You know when it's on as the indicators can be seen from the ISS. It's also got a positive footswitch.
Tiny footprint on a board.

Meh:-
Clearly made in the same factory as EastRock, Donner and others, as it's identical, down to the magnetic flappy box. It also has exactly the same flaw, a loose jack socket. The hole in the case has been cut slightly oversized, so the socket is loose, but the jack itself is a good fit. Mine's in a pedalboard, so accidental disconnection isn't a worry.
Only powered by the socket [due to it's nano size].
No way to adjust frequency from A440HZ.

TLDR:-
Cheap, cheerful, fast but built to a price. Worth that price.

It's a tuner that works. If that's your standard then go for it, you probably can't go wrong for the price.

As for the nitpicks, it's sometimes slow and takes a while to get the note I'm playing right. The button feels kind of cheap. The lights are nice and bright, possibly a bit too bright if you're looking straight down on it, but fine at an angle. They are a lot brighter than the display though, which is somewhat questionable.

Overall, obviously you won't be getting anything fancy for the price, but if you're just looking to get your guitar in tune then this will do the trick just fine.

this tuner is amazing for the price. it's really easy to use and does the job perfectly.

This Harley Benton CPT-20 is an amazingly good pedal. It's nice and small so it fits neatly on every pedalboard.
This tuner is really easy to use: just plug in a 9V adapter and your guitar, push the button and tune your guitar with ease.
The only downside I experience with mine is that whenever the lights switch sides (from too flat to right or to too sharp) they make some noise on my amp, but only very quietly (not as loud as touching your jack cable when it's not plugged in to your guitar)

Overall I couldn't be more happy with this tuning pedal. I would definitly recommend this to anyone looking for an affordable way to tune their guitar.

purchased this to use on my pedal board as i was after something small and not to expensive and this is ideal for the job. the pedal i received is silver all around and not white as it appears in the pictures, this though is not important to me.
the bypass switch seems sturdy enough and when set to tune mode it cuts off the sound to the amplifier so it could also be used as a kill switch. there is a bright led screen that indicates the note being played with indication to whether the note is high or low to adjust the tuning, i have compared this to other tuners that i have and it seems spot on when using for standard tuning or dropped tuning.
it is all metal in construction other than the display screen and i would imagine that this thing will last for years to come.
on the down side this can only be used with a 9v power supply as there is no facility for a battery connection.
also the led lights that indicate flat and sharp notes are not in line with the metal casing, this does not affect the use but is down to the quality of the build.

summary: for what this tuner costs i think you get value for money. i would replace this with the same model if i was to loose it.