The RBC Bearings SJ9718 is a pretty solid choice for tough applications. According to the manufacturer's description, it works well in both sealed and unsealed versions, which makes it pretty versatile and reliable across different environments.

From our research, this bearing is especially suited for things like helicopter rotors, marine crankshafts, and oil field pumping jacks. So, if you're in industries like aerospace, marine, or oil extraction, where conditions can get harsh, this bearing might be your go-to.

The sealed version offers extra protection against dirt, moisture, and other things that could mess with its performance and longevity. This is really helpful in situations where it’s hard to get to the bearings for maintenance.

On the other hand, the unsealed version might work best in a clean, controlled environment where you can maintain or clean it often, and you don't need as much protection against contaminants. This could also save you some costs while still keeping things running smoothly.

When deciding between the two, think about your specific conditions and how often you can do maintenance. If your setup deals with rough conditions and maintenance is rare, you might prefer the sealed version.

But in more controlled settings with regular maintenance, the unsealed SJ9718 could be more economical yet still effective.

All in all, the SJ9718 is built to handle a wide range of industrial demands. So whether you’re working on a helicopter rotor or an oil field pumping jack, it's designed to tackle these challenges well, offering solid performance whether sealed or unsealed.