ERT 300 tennis computer This one is even better. (read the manual, it is quite interesting) http://www.atssports.com/tennis.cfm?prodid=656 But it costs a lot more.
I remember asking someone about this a long while back, and the response was that these are pretty much only valid for tennis, as the scales are calibrated for much higher tensions than what is used for badminton.
Naw, your best bet is getting a digital fisherman's scale. Accurate to 0.1lbs. They are $15-$20 online.
If you do a search, you will find out that badminton stringbed-tension tester is not available at the moment.
I've got a "stringmeter mkv1" made by polycraft, which was originally designed for larger strings than we use. So with a known raquet tension i've set the rotating scale to give me the correct tension for that raquet, and i've found it pretty accurate since.
