Plastic discs 157mm in diameter, with 'necks' which enable stacking of the discs. The necks a above one another to keep spacing for spat to develop. The discs have raised ridges which help the spat adhere to them.
Flipping the cages will control bio fouling and secondary Spat. The OysterGro System is amongst the most efficient system on the market today to control fouling and secondary spat. The two floats (figure V) have been designed specifically for this cage and for this purpose.