Maximize the space on your side shelves with the Side Shelf Accessory Cup Holder. This cup holder belongs to the new lineup of Rail System Accessories compatible with some of Blackstone’s newest side shelf designs. This durable cup holder can hold most 32 oz. cups and features a mug handle cutout to accommodate even more styles. Whether you’ve cracked open a cold one or are keeping a thermos full of coffee on hand, this cup holder has your back!