Slick with previews

      if($('.node-unit-catalog .image .slider-nav .field-item').length > 1) {
  $('.node-unit-catalog .image .slider-for').slick({
    slidesToShow: 1,
    slidesToScroll: 1,
    slidesPerRow: 1,
    arrows: false,
    touchThreshold: 30,
    cssEase: 'linear',
    fade: true,
    asNavFor: '.node-unit-catalog .image .slider-nav'
  });
  $('.node-unit-catalog .image .slider-nav .field-items').slick({
    slidesToShow: 4,
    slidesToScroll: 1,
    arrows: false,
    vertical: true,
    cssEase: 'linear',
    touchThreshold: 30,
    verticalSwiping: true,
    asNavFor: '.node-unit-catalog .image .slider-for',
    focusOnSelect: true
  });
}