JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
  <select class="form-control">
    <option>00:00</option>
    <option>01:00</option>
  </select>

CSS

.form-control {
  width: 60px;
  height: auto;
  display: inline;
  border: none;
  border-radius: 0;
  border-bottom: 1px solid black;
  padding: 0;
  box-shadow: none;
}