2 inches across and comes with a fancy adjustable necklace. I've made these so the cord can easily slip between the head and back tentacles. there are no gaps for the cord to slip through so don't worry about it falling off
If you want something a little more classic looking i offer these silver necklaces which can be purchased separately:
20 inch: http://www.etsy.com/listing/76584512/20-inch-sterling-silver-plated-necklace
22 inch: http://www.etsy.com/listing/78467972/22-inch-sterling-silver-plated-necklace
24 inch: http://www.etsy.com/listing/128358526/24-inch-sterling-silver-plated-necklace
NOTE: The pictures are representative and not of the actual item. I can make these nearly identical to each other but since it is handmade slight variations between each one will occur
**** BEFORE ORDERING, PLEASE READ MY SHIPPING POLICIES - http://www.etsy.com/shop/EmergentGlassworks/policy ****
Have any questions? Contact the shop owner.