In order to solve the limitation of center distance adjustment and strength distribution of conventional gear. a structure with the same base pitch but different modulus was proposed to greatly improve the strength of small gears in gear transmission. especially the strength of the tooth root. But used in the engineering practice in modulus differ with tooth profile angle are smaller. https://safeersappliancers.shop/product-category/faber-heaven-lite-90cm-x-50cm-white-glass-ceiling-hood-wh-350-0529-509/