JSFiddle - React, Tailwind, and code Playground

HTML

<div class="flag">
  5 Items
</div>

CSS

.flag {
  width: 110px;
  height: 56px;
  padding-top: 25px;
  position: relative;
  background: red;
  color: white;
  font-size: 11px;
  letter-spacing: 0.2em;
  text-align: center;
  text-transform: uppercase;
}
.flag:after {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 0;
  height: 0;
  border-top: 13px solid #eee;
  border-left: 55px solid transparent;
  border-right: 55px solid transparent;
}