Autonics SFDL-SDK Series is a safety door lock switch designed to prevent accidents by ensuring that machinery is not operated when a worker is in the working area. It has a lock out function that can be activated using a key, and it can be installed on a 40mm x 40mm aluminum profile or door that weighs less than 20kg, The SFDL-SDK Series is made of durable materials and has a mechanical durability of at least 20,000 times. It also comes with a spring strap for the lock out key to prevent it from being rolled into the machine.