Schaller BM Light 4L CH

VERY light, helped a ton with my '70s-style Thunderbird with the huge headstock, but they do feel fragile from the lack of weight.
The major drawback though is the installation, you need to drill an extra hole for each tuning key, unless your bass has already got keys with that kind of mounting from the factory (which is very rare).
I don't regret buying them but I'd rather go for the Schaller M4 90, so I don't have to alter my instrument that much.