Hook for your Invisilign and retainers.

Also great as a pick to remove debris from you molars before you put your trays back in.

It's easiest to use at the back inside of the tray, this gives the most leverage for removal.

It is designed with a non-tangent bottom fillet to help with printing flat on the build plate.

I advise to print with no brim but you'll need to make sure you have good bed adhesion. The brim makes the edge sharp and can cut your lip if you don't smooth if out. Do whatever works for you.