Hi Helena,

Thanks for your question.

Whatever the overall size of the zip and link set you have is the size of protector you should look for. For example, a Super King Size is 6FT x 6FT 6IN.

Alternatively, if you separate the beds from time to time you may have to look at single size protectors.

Zip and Link mattresses should only be slightly different in terms of measurements, if at all.

I hope this has helped answer your questions fully but if you do have any further queries please don't hesitate to contact our office on 0161 437 4419.

Kind Regards, Lee.