I've not had the same issues as the previous reviewer. They're an adapter, allowing you to run shimano cranks on bb30. Fitting new adapters to a new bike with a crank in good condition, with appropriate grease/loctite etc, and I find I get a year/6000kms before I replace the bearings. Yes they creak every now and then, but that's usually because the rain has washed out all the grease. Redo it and adjust again after one ride and it's back to almost silent.

Bought to convert a Cannondale CAADX frame to run Shimano 24mm-axle cranks, this is easy to fit - just remove the existing chainset and push the adaptors into the BB30 bearings. While it'll allow you to run Shimano, don't expect it to stop any of the infamous BB30 creaking. It doesn't. In fact, it's made the situation far worse, destroying a bottom bracket inside 5 months, forcing me to buy a better adaptor.