The number 50 in the product name means it uses 50mm dynamic drivers, which Shure custom-engineered.
Shure AONIC 40 Wireless Noise Cancelling Headphones is actually the first Shure product that I owned. As the number 40 in the product name suggests, AONIC 40 has a 40 mm dynamic driver which makes it in the same range as the Sony WH-1000XM4 Headphones and Apple AirPod Max.
AONIC 40 is Shure’s mid-range wireless noise-cancelling headphones. They have another higher-end which is the AONIC 50.