Our library system does not like them. The locks are hard to get off. We use a rubber mallet to pound on the top of the case when it is on the key because it is too difficult to do by hand. To have to do it by hand on the key all day is very hard on the employee's hands. Also, the placement of the security strip is not good. After a time, it will start to come off and cut an employee's hands. The system obviously was not tested for any length of time or these problems would have come to light. It looks good on paper but does not work well in the real world. All items were of poor quality. We are stuck with them since we have so much money invested in them.