mc21

.sky-mega-menu > li > a {
  position: relative;
}
.sky-mega-menu > li:hover > a:not(:last-child):after {
  content: '';
  position: absolute;
  border-right: 14px solid transparent;
  border-bottom: 14px solid rgba(255, 255, 255, 0.9);
  border-left: 14px solid transparent;
  margin-left: -14px;
  bottom: -30px;
  left: 50%;
}