Your Quiet pro mixer grinder comes with two different specialized blades: one is the Dry Blade (minus shaped) , and the other is the Wet Blade (plus shaped) Please see image below for reference.
These two blades are used for diﬀerent purposes like dry grinding and wet grinding.
The Dry Blade is used for grinding all dry masala, tomato puree, onion paste etc. The Wet blade is used for grinding dhal batter, baby food, rice batter, lassi etc.
How to replace the blades
To replace the blade, hold it and rotate the blades inside the jar in clockwise direction using spatula while holding the coupler ﬁrmly. While fixing another blade then rotate it in anticlockwise direction and ensure as blade is proper locked before using the appliance.