The CubeCap® is one of the first environmentally safe solutions available. In addition, you are able to recycle and reuse the CubeCap® thus saving on costs. The CubeCap® deprives the cube of its light by reflecting it back up towards the plant and away from the top of the block. The CubeCaps® patented technology allows the necessary air exchange by way of its unique elevated, vented design. Designed for use with 3 in, 4 in, and 6 in rockwool blocks.