Blenpar Replacement 6 Fin Blade Compatible with Nutri Ninja Auto IQ Blenders Only Compatible with 900W 1000W Nutri Ninja Auto-iQ Blenders. Measure the outside diameter of the blade or cup and it must be 3.94" which is almost 4" There are two types of blade that fit Nutri Ninja. Please check your blender to see if the gear has 6 fins or 7 fins. None of these part fit the Ninja blenders that take 16oz cups. They do NOT fit Magic Bullet, Nutribullet This is an aftermarket item made to fit Nutri Ninja Blenders FEEDBACK: We will leave feedback after receiving a feedback. If for any reason you are dissatisfied with your purchase, please contact us immediately before leaving any NEGATIVE FEEDBACK so we resolve whatever issue you may have. 100% Customer satisfaction! Sales Tax: CA residents will be charged Sales Tax SHIPPING: Orders are usually processed within 24-48hrs. All weekend purchases are shipped Monday. CONTACT US: Have any question(s) contact us in contact seller. RETURNS: Returns are accepted but must be authorized in advance.