When you get a Chris King bottom bracket, you are buying a product that's designed and built to last a long time, and part of the design is serviceability. In keeping with the precision of the parts themselves, Chris King has made tools that are built to the same exacting standards as the products they're made to service. From grease injectors that allow you to flush the old grease out and replace it with new, to installation tools for all variations of threaded bottom brackets, these tools make it easy to ensure that your bottom bracket will last as long as it can.
We love Chris King's grease injector tools because they make servicing a bearing incredibly quick and easy. The process is as simple as removing your cranks, pulling the plastic spacers out of the bottom bracket, pressing the grease tool in until it bottoms out, pressing your grease gun onto the zerk fitting, and pushing grease into the bottom bracket while rotating it to spread the grease evenly through the bearing. Once you see clean grease coming out, you know you're good to go, and you can reinstall the plastic spacers in the bottom bracket, reinstall your cranks, and go ride!
If you're curious to see the greasing process, here's a video that shows the process pretty clearly.