These bespoke, high quality mounts will be cut to size in our Shropshire workshop. Once ordered, please send us the outside measurement and aperture size that you require. Remember to take approximately 6mm off your subject size to create your aperture size - this ensures enough overlap of your subject to avoid it falling through the aperture. If you require a mount with outside measurements that are larger than A4, please get in touch with us to see if we can help. Thank you.