Sherwood has released a 29000 impeller which is the same as the 18000 impeller with the exception of the insert. The 29000 impeller uses a 10 tooth 45 degree splined impeller whereas the 18000 used a 14 tooth 30 degree spline.

Sherwood has also released a 30000 impeller which is the same as the 22000 impeller with the exception of the insert. The 30000 impeller uses a 10 tooth 45 degree splined impeller whereas the 22000 used a 14 tooth 30 degree spline.

The part numbers of the 29000 and 30000 are molded into the ends of the impellers for identification. Additionally, the 29000 and 30000 can be identified by observing 10 spline teeth vs 14 teeth previously used on the 18000 and 22000 impellers.