Suspension files come in 2 main sizes - A4 and Foolscap
Choosing the right size in key and it is very easy to select the wrong option if you aren't aware of the difference.
Foolscap Suspension Files
Foolscap Suspension Files are the most common size and are used in standard office filing cabinets. These files have a width of 407mm from hook to hook. Foolscap will give A4 paper more space on either side to avoid the papers becoming bent and damaged.
A4 Suspension Files
A4 Suspension Files are slightly smaller than Foolscap and are generally used in home office cabinets or metal filing boxes, pedestals and A4 filing cabinets. These files measure a width of 350mm from hook to hook.