Phiten Aqua Air Light Blue Titanium Necklace 20 Inch WA0005B.

The Air Necklace is an ultra-light version of Phiten’s trademark necklace, conceptualized and tested by world-class marathon runners asking for something lighter to reduce necklace bounce.
The Titanium Silica Foam Core cuts overall weight and is formulated specifically for those times when every ounce counts.
The fabric shell is a mixture of highly elastic polyurethane and nylon, which allows for a claspless design that stretches effortlessly over the head.