Gamma Sports Tension Calibrator for Tennis Stringing Machine & Badminton Stringing Machine - Compatible with All Machines, Tests up to 90 Pounds of Tension

Great tool to monitor tension on stringing machine.

TL;DR: The calibrator itself is accurate and easy to read, but the included string is weak and snapped at load. Plan on replacing the string with something sturdier and you will have a very useful tool. I bought this Gamma tension calibrator to double check both a crank machine and an electronic constant pull machine. For that core purpose it does its job very well. The body feels solid, the piston movement is smooth, and the printed scale is easy to read at a glance. I like that it measures all the way up to 90 pounds, which gives enough range to check anything from soft badminton setups to very tight polyester tennis jobs. In use, the calibrator is straightforward. Clip it to the tension head, pull to your target setting, and see how close the reading is. Once I accounted for a little natural variance, it gave me consistent results and helped me verify that my machines were pulling lower than what the display claimed. From a calibration perspective, I trust the readings and would recommend it. Where this product falls short is the string that comes with it. Under load the provided string snapped. It feels more like a generic scrap of tennis string than a purpose built connector. For this tool, the string is not hitting balls or dealing with friction in grommets. Its only job is to be durable and hold a static load. I would have preferred a thicker, non stretch cord or cable that is clearly overbuilt for the maximum 90 pound rating. The calibrator itself survived the incident just fine, but having the string fail mid test is not ideal. The simple fix is to replace the supplied string immediately with a sturdier alternative. An old piece of thicker synthetic gut, Kevlar, or even a strong cord looped and secured properly works much better. Once I did that, the tool became completely reliable and I could focus on adjusting my machines rather than worrying about something snapping. Overall, I see this as a very capable tension gauge paired with a mediocre piece of string. If you are comfortable swapping out the connector right away, the value is still good. You get an accurate, compact calibrator that works across different machine types and gives you confidence that the tension number you dial in is the tension you are actually delivering. Thanks for reading!! (Assuming you did…)

Works perfectly and allowed me to properly calibrate my stringer (Ektelon Medel H).

Hasn't failed me and easy to use.

It is so easy to hook up to your machine and get the tension correct. If you need one for your crank machine pick it up now!

Yes, it does work. Minor problem is that it is not that easy to read the scale. It's a line and you won't be able to read 1/2 lb or 1/2 kg. You don't have to get a "tennis" string calibration. It's just a weight scale. You can get digital weight scale that fisherman used. I bought this and digital weight scale. Used both to pull each other and the numbers came out the same for both. In conclusion, it's just a weight scale, and you can get a digital pull weight scale at the same price and it is more accurate down to ounces.

The quality is good. It felt heavy in my hand. But the measurement is very hard to read. You can only get a rough tension read, not an precise one. so I returned it the next day.

The one big issue with using this calibration tool is that it is difficult to read the values/measurements