The Defense Turrets #2 is a multi-piece set that comes with four individual turrets with both a swiveling twin barrel gun and a machine gun all cast from resin.

Each hatch is 0.8 inches (18mm) in diameter 0.20 inches (5mm) tall and will fit into a 0.7 inch (18mm) diameter hole.  This hatch will work on most Games Workshop Space Marine and Imperial Guard vehicles.