Access Control Keypads These high quality keypads contain the latest in "Piezo" technology. The sensors embedded below the metal surface of the keys on all Padde Piezo keypads are made of a ceramic alloy that only needs capacitance to activate. There are no moving parts to wear out. All numbers are laser etched for years of use without wear. ES634 & ES626 Keypads S200 Blue Keypad Trimec ES634PP Combination Keypad & Wiegand Proximity ReaderCombined reader and Piezo keypad.