I bought this motor to replace my old one, which no longer worked. The new one works perfectly with my older blade assemblies and containers. Note of Caution: Look inside the top of the motor and the bottom of the blade assembly and you will see that the system works because of interlocking teeth. These gears/teeth are made of plastic. If the blade assembly should freeze for some reason, the motor will keep spinning and wear out its toothed gears very fast. This means the motor is no longer useful. This is what happened to me, and why I had to replace the motor. The plastic sealing ring in the blade assembly came loose, locked around the blade, and froze it. The gears in the motor very quickly wore down to nubs. End of motor. I didn't understand what was happening; by the time I did, it was too late. This isn't a criticism of the unit, just a note to be aware of what can happen, and why I needed to replace the unit. Also: Never run the motor for more than a minute--less really--or you will start to smell it burning.