Net Cup Lids: Root Guard 

Root Guard lids protect your plants' roots from debris and light. Root Guard lids are made to fit the "Flex Nets" and snap on tight. They'll work with all comparably sized net cups but may not fasten to the rims. 

The white color reflects the growlight so no heat is absorbed to damage the plants' roots.

Root Guard lids also help prevent algae growth on the growing medium by blocking out the light.

Fits on the top of the net cup with a center hole to fit around the base of the plant.