The A3PB41-600B-10 is a 44mm mushroom-head pushbutton with a black actuator, two-position momentary action, and a single normally open (1NO) contact block. It is used as an emergency-stop or palm-actuated command device on control panels, machinery, and conveyor lines where a large, easily reached operator is required.
What the description means for fit
The 44mm mushroom head is a standard emergency-stop operator diameter. The momentary action means the contacts return to their normal state when released.