The Schneider Electric XB6CA25B Black Square Flush Complete Pushbutton Ø16 Spring Return 1NO+1NC Unmarked is a black, square, flush-mounted pushbutton with a spring return and no marking. It is 16 mm in diameter and has two normally open (NO) and normally closed (NC) contacts. The button is made of plastic and is rated for 250 V AC and 6 A.