TOOGOO(R) Red Mushroom Emergency Stop Push Button Switch

Can this be something to use as emergency button in an office building for each of the office rooms?

The image on item page shows a gray&black box. When you add it to your cart the image in the cart shows the box is yellow&black. Which on is it?

What is the current and voltage rating of button?

Is up no or don button nc? what does self locking mean?