In the large tournament display, the times are shown delayed.StackMats, which required two hands to stop and so signal the solvers' intention that the solve is complete, was deemed a better solution. Among the reasons for the adoption of StackMat was the real possibility of accidentally dropping the cube, especially during a one-handed solve. This timer used a light sensor, which is stopped by when the solved cube is placed on top. The major rival was a timer developed by the official Rubik's brand around 2003. When the World Cube Association was founded later in 2004, StackMat timers were adopted as the official timer. Tyson Mao used them in the first Caltech competitions in early 2004. Gen-1 (Generation 1) StackMat timers were first used in World Championship 2003 and in all following official competitions until they were replaced with the Gen 2 and up. QJ has 3 models, but the 1st gen timer is not produced anymore. QJ timers are much cheaper than SpeedStacks timers, but only of their timers (3rd gen) has a data port, and none of the QJ models have a data storage feature. The upside to the YuXin, however, is that they use AAA batteries unlike the SpeedStacks StackMat's batteries. They also are known for playing annoying, cheesy sounds which can be turned off.
![official rubiks cube timer official rubiks cube timer](https://www.davidcube.com/images/YuXin/ZhiSheng/YXTIMERV2/YXTIMERV2.jpg)
They are, rather, accurate to the 0.016 second. However, the YuXin timer isn't accurate to the thousandth place like the SpeedStacks StackMat.
![official rubiks cube timer official rubiks cube timer](https://d4yxl4pe8dqlj.cloudfront.net/images/9a2006ae-32e1-4798-b93a-cd714d4b0528/3113b85a-e6eb-4d70-b08d-ada0df6c9a94_large.jpg)
The YuXin timer can save times, like the SpeedStacks timer. The YuXin timer is much more widely used than the QJ timers, and are very cheap as well. At least the Generation 2 timer must be used. There are three major brands of stackmats, the QJ, YuXin, and the SpeedStacks, but only the SpeedStacks one is used at competition and it is the most widely used timer brand due to their reliability and accuracy. 3.1 Accuracy (timer frequency distribution) issue.