Cool hover-effect using :after

hovereffectusing:after

<div class="wrapper">
    <div class="circle"></div>
</div>

.wrapper {
    background: #000;
    width: 100px;
    height: 100px;
    position: relative;
}
.circle {
    width: 50px;
    height: 50px;
    background: #fff;
    position: absolute;
    left: 25px;
    top: 25px;
    border-radius: 50%;
}
.circle:after {
    content: "";
    display: block;
    position: absolute;
    top: -8px;
    left: -8px;
    width: 100%;
    height: 100%;
    box-shadow: 0 0 0 2px #fff;
    padding: 8px;
    border-radius: 50%;
    transition: all 0.5s ease;
    opacity: 0;
    -webkit-transform: scale(.8);
    transform: scale(.8);
}
.circle:hover:after{
    opacity: 1;
    -webkit-transform: scale(1);
    transform: scale(1);
}