why not go to the Bose website and look at the various pictures of headphones and see which picture matches your headphones. All you need is the name such as the QC35. You will find that many of the Bose over ear headphones for example use the exact same size replacement cushions. You can buy then from Bose or if you choose, you can do a search for the name of your headphones and ear cushions on sites such as eBay or Amazon to name two.
You can identify your product by entering the serial number HERE. If you're unsure where to find the serial number, click 'Find my product, serial number, or 4-digit code'.