Tried mine out today and
really pleased with it...
This is my tuppence :
First off its really lightweight, but very neatly made - quite unbelievable for £18 delivered from China.
It consists of the electronics and display sitting above two sensors with a vee block and clamp to align your barrel with these sensors.
The top clamp can be removed and a larger 'U' clamp used for guns with moderators or foresights this keeps everything in line and removes the chance of 'accidents'...
Or you can leave off the clamps and just rest the barrel on the vee...
(Its worth noting there is also a second version with 2 rows of IR leds which has no clamp and you shoot through for about £25 if you prefer.)
The instructions are completely in Chinese with not even a picture in sight, but in reality its not a problem as it is simple enough to use its basic function of being a chrono...
Press button to turn on, wait a few secs while it cycles through a self test, when the two dashes come up on the screen its ready.
Shoot, read speed off, repeat, press button again to cycle back through shot results, long press to turn off - simples.
The speed reads in metric only - to one decimal place below 100m/s and to whole numbers above.
I believe it max's out at about 800m/s - but don't quote me on that.
There are some translated instructions about including it's energy calculation features - but I'm still trying to locate them...
But the important things are - is it accurate and reliable?
Accuracy - I also have a Chrony F1 and using a multi-pump Crosman which is ultra-consistant it certainly is...bang on the money from 270fps right up to 750fps.
Reliable - this is the winner
every shot read, every time and not at all ambient light fussy. Now as whether its reliable long term? - its too early to tell...buts lets just remember that price
£18...!
Final verdict : Love it....