What is sr-only in Bootstrap 3?

Question

What is the class sr-only used for? Is it important or can I remove it? Works fine without.

Here\'s my example:

Answer 1

The .sr-only class hides an element to all devices except screen readers:

Skip to main content Combine .sr-only with .sr-only-focusable to show the element again when it is focused

.sr-only {
border: 0 !important;
clip: rect(1px, 1px, 1px, 1px) !important; /* 1 */
-webkit-clip-path: inset(50%) !important;
    clip-path: inset(50%) !important;  /* 2 */
height: 1px !important;
margin: -1px !important;
overflow: hidden !important;
padding: 0 !important;
position: absolute !important;
width: 1px !important;
white-space: nowrap !important;            /* 3 */

}