The unit uses a simple, rotational Ellis lock mechanism that is ideal for small valves due to its compact design. It has an Acetal plastic body, which is lightweight and well suited for use with small diaphragm valves. It is also highly resistant to moisture, solvents and many other neutral chemicals.

Despite this, it is tough, hardwearing and has a high resistance to repeated impacts. The Ellis key has a spring-loaded rubber seal, preventing water ingress during washdown or sterilisation procedures.