Bigger Faster Stronger sells a similar device for $80. You would have to make sure you set it right -- variance in the position on your leg will cause major differences in when it beeps.
I haven't. I have heard mixed reviews. I'm doing 2 things now... I stretch a band across the power rack at the appropriate height. When my butt touches the band, I know I'm good. I also video my squats and watch it after each set. This is obviously the best way to tell.
The band idea is a good idea, you just need to make sure your feet position are the same everytime. If your feet are too close to the band, your hamstrings will hit early. Too far ... go below your depth gauge.
Not trying to nit-pick, but hamstrings actually won't hit early. At good depth, your butt will be the lowest part of your thigh. But your point is true.
The gent that invented the sq precision has been working out with me on Saturdays. I think the device is solid and very helpful if you train alone. Very loud "beep"
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""Training is efficient if the highest sports result is achieved with the least expense of time and energy" - Thomas Kurz
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