I am very satisfied with it. I have used it several times now. I would say it is pretty sensitive to the movement, speed and g force. For the price I got this, believe me, it is worth the money. I am pretty happy about it.
I am also very satisfied with the instruction and how simple is to use it. It is not a complicated device you will be spending/waisting time to find out how it works. I also appreciate the fact that it is cordless and can be used on any car as needed. Very practical.

Very easy to use and work perfectly.
1/4 Mile and 0-60 Mph. time tested with real drag track system
and the K.A.T. Matrix give exactly same results. Very accuracy.

The Matrix works great. Easy to use, easy to read even at speed. It mounts great and seems to be a very quality item. Would buy again!!!

I bought this because I just bought a 1972 Monte Carlo with a 350 sb, all original and wanted to see what she would do. The local 1/4 mile strip closed down recently and there is no others within a 5 hour drive. The price of this would cost the same as gas. It does 0-60 time, 1/4 mile time AND speed and G forces as you are turning, accelerating, and stopping. You cannot do all 3 at the same time, it is one setting at a time. You follow the directions to put in the weight of the car and driver and the testing parameters(range of miles per hour, e.g.: 30-70 mph) and it will give you an estimated wheel horsepower within the parameters which is pretty cool. The mount has 3 suction cups to hold to the windshield securely. The time and speed are consistent. My best time is 14.7 @ 103 mph with a max HP of 225 at the wheel. Statistically, it is correct and the numbers all match. If the track opens up, I will test it on the strip. Alibaba.com wholesales this for about $20 a piece but you have to buy 18 at a time. Might be a good investment. I bought this from Amazon for $58 and they have sales every once in a while so look for that.

Works as advertised. No issues.