#slider-left {
    background: url('../img/stlk-1.png') no-repeat center;
}
#slider-right {
    background: url('../img/stlk-2.png') no-repeat center;
}
#slider-left a.bx-next, #slider-right a.bx-prev {
    padding: 20px;
    color: transparent !important;
    font-size: 40px;
}