English to Arabic Bus/Financial Real Estate

I need appropriate translation for the term "cap" which is used in a real estate management software, and here are two definitions:

1-A provision of an adjustable-rate mortgage (ARM) that limits how much the interest rate or mortgage payments may increase or decrease. See lifetime payment cap, periodic payment cap, and periodic rate cap.

2-Adjustable Rate Mortgages have fluctuating interest rates, but those fluctuations are usually limited to a certain amount. Those limitations may apply to how much the loan may adjust over a six month period, an annual period, and over the life of the loan, and are referred to as "caps." Some ARMs, although they may have a life cap, allow the interest rate to fluctuate freely, but require a certain minimum payment which can change once a year. There is a limit on how much that payment can change each year, and that limit is also referred to as a cap.