XB4BW34B5 is a Harmony XB4 illuminated push button - 22 mm chromium-plated metal, flush red, spring return, 1NO+1NC, 24V LED.

Why a metal 22 mm button on a washdown machine?

IP66/IP67/IP69/IP69K with a 7 MPa high-pressure washer rating means the LED stays lit through the hose-down that breaches IP65 plastic units. The chromium bezel also survives physical knocks a plastic collar cracks. The alternative - a plastic 22 mm button - is fine dry but fails the first foam-and-water cycle.

What does the illuminated contact do electrically?

Integral red LED at 24V, 1NO+1NC slow-break with positive opening, 6A, screw clamp - one unit gives a lit operator cue and a normally-open plus normally-closed contact for the logic. The alternative - a non-illuminated button plus a separate lamp - doubles the panel cutouts for the same function.

Where is it the wrong choice?

At -25 to 70 C it covers most cells, but the flush red is one of many head options; if you need a mushroom E-stop, the XB4 range has that separately. The alternative for a guarded stop is a dedicated emergency-stop unit, not this illuminated push button.