As set of three 30cal Browning machine guns, three 50cal browing machine guns and three AFV bow machine gun barrels in 1/72nd scale.
They were designed for use for the turretless M3 stuart version which can be used with The Plastic Solder Company's kit and the lower hull I designed here -
https://www.shapeways.com/product/MHFR8CVBR/stuart-r-lower-hull?li=shop-results&optionId=12353946
The parts could be used on other 1/72nd scale American AFV models.