SC. The Alpro 626S-200 is a simple to install and user friendly keypad suitable for up to 200 users. The unit uses solid state piezo technology with no moving parts, and anodised graphics for long life and wear resistance. Ideal both externally and internally it is IP68 rated and comes with a 5 year guarantee.. Tamper resistant (solid metal housing). Touch sensitive buttons - solid state piezo technology. Sample code programming. Non-volatile memory