Native Treasure - Smooth White Clam Puka Shell Necklace with Real Shark Tooth Pendant - 18" Inch Standard 18" Length. Should fit up to a Size 16.5" Shirt Collar Size 5mm (1/4") Class 'A' Quality Flat Cut Round White Clam Shells 3/4" Gem Quality Whitetip Shark Tooth Pendant Includes FREE Stainless Steel Beading Wire Upgrade, Silver Plated Trim, Sturdy Twist-Barrel Lock Exclusive 60 Day Free Breakage Replacement 100% Satisfaction Guarantee