This is an electric door strike, which is extremely durable. This isn't surprising considering that it is produced with quality stainless steel. Besides that, it accepts voltages that range from 12-volts to 36-volts. The strikes are designed to be used for extension lips, which is why they are pre-drilled. Also, if you choose the 20M model, then you'll enjoy its "anti-tamper" feature, which is patented. The bottom line is the strikes are among the most durable in their line. As a standard, the strikes in this series do come with a 10mm strike lip. This is designed to prevent injury to the user, as well as cause any damage to the clothes they are wearing. In addition, the strikes have been approved by the SCEC, which means they can be used in secure areas. If you have any questions about the FSH FES20 Electric Door Strikes, or any of the products and services that we offer, please do not hesitate to get in touch with us on . We would be happy to answer any questions that you might have.