Fits most standard 20oz stainless steel tumblers. Also fits on ALL counter tops, work desks, coffee tables, bathroom vanities, and night stands. Use a cable and clip the NARWHAL on any cooler bag, golf bag, backpack, ski pants, etc. Take your tunes everywhere you go! Bluetooth Connectivity, IPX6 Water & Dust Resistant, Rechargeable Battery, Speakerphone, Stereo Sound (Link Any 2 Speaker Lids Together).