Thispretty lower half was recently found lying empty in deep-water off Oahu, Hawaii.The longest dimension (diagonal) is 25.5 mm, the right angle “height” is 24.9 mm. Measurements were made by dial caliper and rounded down to the nearest whole 10th of a millimeter. Size comparison to US coins: Quarter = 24mm; Nickel = 21mm; Penny = 19mm, Dime = 17mm Items are shipped within 1 business day of payment Shipping cost combined for multiple wins Please wait for me to send an invoice if you’ve won multiple auctions of mine. That way I can ensure you are charged shipping only once! : ) US Domestic – 1 st Class –$2.00 Priority – $5.20 Contact me prior to submitting payment if you want Priority Mail and/or insurance . International – Shipped first class- Please note $87 per box US Fish and Wildlife Service export fee outlined in this listing. (This is in addition to postage) Contact me prior to submitting payment. Your satisfaction is guaranteed. I will give a full refund upon return of the shell if you are not satisfied. Please feel free to contact me any time!