Brittany Birch Double Points. Most people use the shorter (5) needles for socks! The other sizes are 7.5 long.
Neko Curved Double Point Needles is a similar needle: double point and US 17 (12.0mm) US size. You may also like Jimmy Beans Wool Jimmy's SmartStix Double Pointed Needles, which is another similar needle: double point.
You may enjoy taking a look at the Spud & Chloe Outer TC's Cozy Hat, Blue Sky Fibers Bulky Cardiff Coat, Blue Sky Fibers Bulky Baby Hat , and Rowan Big Wool Cardigan Bay Jacket kits all using Brittany Double Point Needles.