Not fit for 7 fins or 6fins ninja blender blade. ② The Ninja blender has 5 male fins (not 7 fins or 6 fins). ④ Before use, make sure the 5 fins blades are firmly screwed onto the blender cup. They compatible with Ninja QB series QB3001SS QB3000 QB3000SS QB3004 QB3005 QB3000SSW-30 QB3000QR-30 QB3001SS-30 QB3000QBK QB3004 QB3005.