The M2B miniature pushbutton switches feature an interior O-ring surrounding the actuator within the bushing, keeping out harmful contaminants. The bushing and the housing top both have single-unit construction. Terminals are epoxy-sealed to keep out contaminants as well. Their minimum lifetimes are 25,000 operations for silver contacts and 100,000 operations for gold contacts. Single- or double-pole double-throw momentary types are available. There's also a choice of two different plunger lengths and four cap diameters in various colors. Pricing is $2.79 each in 1000-unit lots, and lead time is stock to six weeks.