Piezo Switches can be very effective where the interface calls for reliable performance in extreme conditions.
Finger pressure on the surface of the housing causes the housing to flex very slightly (approx. 2 microns)
Pressure activates a piezo crystal which emits low level a signal which is amplified by electronics built into the housing.
No moving parts so reliability is typically >20 million cycles
Tamper proof housing
Impervious to weather, chemicals, beverage spills etc
Available in various housing materials
Requires no external power source
Highly resistant to external impacts
Anodized or Powder Coated Aluminum