They worked great on my Gas Gas as the front tire was out of balance. Just found the heavy spot by spinning the wheel and finding the place where it settled to the bottom. added the weights on the other end about 4 spokes apart. they crimped on easily and the vibration is gone. I used the 10 gram weights and have extras for future use.
Crimping these weights is difficult because the spokes are thin on a KTM dirt bike and require a lot of pressure to "bite" the spoke. Also a person needs to get a dedicated pair of strong pliers and grind the jaw teeth smooth, otherwise the sharp teeth destroys the nice clean appearance of the weight.
Not certain of specifics, but it's a softer metal that was easy to mold around the spokes. Have had them on for months of hard riding with plenty of river crossings, mud, etc and they aren't rusting or anything either so I've been happy with them.