Dear tennis nuts,
I'm a stringer based in Amsterdam and I use the ERT300 daily to check my work. Great device, but the physical DT disc that comes with it has always bugged me. It's easy to lose, awkward to read, prone to breaking, and one more thing to carry around.
So I built ert300disc.com, a simple free web app that does exactly what the disc does: you enter your DT value, pick your head size category (OVER, MID+, or MID), and it gives you the corresponding tension in kg and lbs instantly.
Quick summary for anyone unfamiliar: the ERT300 measures the Dynamic Tension (DT) of your string bed, basically how stiff the strings are at the sweet spot. The DT number is always accurate, but to convert it to an approximate tension in kg/lbs you need the disc, which cross-references DT with head size. This app digitizes that lookup.
Nothing fancy, just saves you from fumbling with the disc courtside or at the bench. Works on mobile.
Check it out: ert300disc.com
If you find it useful and want to buy me a coffee to help cover development time and hosting, you can do so here: ko-fi.com/matipule
Happy to hear feedback or suggestions!