When selecting Cross Metal Domes (also known as four-leg tactile domes), you must prioritize actuation force (trip force) and click ratio. The actuation force typically ranges from 100g to 500g, depending on the tactile feedback required. Ensure the click ratio is between 40% and 60% to provide a crisp user experience. Additionally, verify the travel distance (usually 0.2mm to 0.5mm) and the life cycle rating, which should ideally be over 1 million actuations for industrial or medical-grade applications.