If a prison rule is rationally related to a legitimate interest, what is the test for such a rule?

Where appropriate, we must also look to see if the prison rule is an "exaggerated response to prison concerns." Turner v. Safley, 482 U.S. at 89-90, 107 S.Ct. at 2261-62. In order to determine whether a rule, even if rationally related to a legitimate interest, is an exaggerated response, we must balance the importance of the prisoner's infringed right against the importance of the penological interest served by the rule. We must also examine the strength of the logical nexus between the penological purpose served and restriction of the prisoner's rights.