This type of dome array (metal dome sheets) is somehow similar to single layer dome array by means of snap dome contacts attached under Maylar. But the difference is that, in this type, the Spacer is attached under the snap contacts. Life testing has shown an increase in the ability of this design to retain the dome on the circuit over the traditional spacer design and an even higher increase in this retention ability over simple domes on adhesive.

Characters of double layer dome array:

1. Light & small
2. Damp proof, heatproof, cold proof
3. Dustproof is done on the snap dome, and oxygenation of snap dome has been avoided