Before you sign any mortgage papers it would be a good idea to make sure your mortgage has a "lock in" clause. Don't know what a lock in clause is? Wouldn't know one if you stepped on it? Here's all you need to know.

A lock in clause in a mortgage agreement is language guaranteeing that the agreed upon interest rate will stay the same until the closing of the sale. Usually lock in clauses are good for 60-90 days so if your closing extends beyond that you probably won't have lock in security.

The purpose of the lock in clause is to guarantee you the interest rate you agreed to. Without a lock in clause the interest rate could change before the closing.