Brittany Birch Double Points. Most people use the shorter (5) needles for socks! The other sizes are 7.5 long.
Knitter's Pride Nova Cubics Platina Double Point Needles and Knitter's Pride Nova Platina Double Pointed Needles are both similar needles: 5", double point, and US 6 (4.0mm) US size.
You may enjoy taking a look at the Blue Sky Fibers Bobbi Bear, Blue Sky Fibers Bulky Cardiff Coat, and Blue Sky Fibers Bulky Baby Hat kits all using Brittany Double Point Needles.