Chris is a USPTR Coach and Professional Stringer with over 10 years of experience. Below is his review on the Tennis "String Thing" tool that is being sold on TV.
It is designed to be rolled along the string bed and is claimed to be made of a very durable plastic material. I was a bit skeptical when I saw this $20 product...
Tennis String Thing Review
I purchased the "String Thing", hoping to find a product that could make the stringing process faster.
After stringing a racquet, I spend a few minutes straightening the strings. While the strings are relatively straight coming off my machine - they are not perfectly aligned. The straightening is more for aesthetic purposes than for performance. I do not subscribe to the belief that a few misaligned stings dramatically affect shots.
Dealing with Crooked Strings
The most prevalent issue after stringing is the bowing affect on the crosses (horizontal strings). Straightening is usually done the fingers or a flat tipped awl. After using the String Thing device on a few string jobs, I found it to be less effective than using an awl or your fingers. This device does a reasonably good job on the mains (vertical strings), but an extremely poor job on the crosses. It makes little to no difference on the crosses.
The effectiveness of this device also depends on the type of string used and its tension. I tested this device on multifilament, nylon and polyester strings. This device is pretty much useless on polyester strings and marginally effective with multifilament and nylon strings.
The device works better when the tension is very low. I found that for this device to work at its best, you would need to use nylon strings strung in the low 50s or lower. This is a non starter for most serious players.
As far as using this device on the court, I believe that using your fingers is a better option. If the string bed is completely misaligned after every point, you need to have your racquet restrung. For players who hit with pace, a very loose string bed typically indicates imminent string breakage. My advice is save $20 and skip the String Thing.
YouTube Review by Inspired Tennis