Under the hood, this element is an input checkbox, but it has a different design.
<!-- toggle -->
<form class="ui-form">
<fieldset>
<!-- default -->
<div class="ui-form__group">
<div class="ui-toggle">
<label>...
<input type="checkbox" name="a">
<span class="ui-toggle__bg"></span>
</label>
</div>
</div>
<!-- checked & disabled -->
<div class="ui-form__group">
<div class="ui-toggle">
<label>...
<input type="checkbox" name="a" checked disabled>
<span class="ui-toggle__bg"></span>
</label>
</div>
</div>
</fieldset>
</form>