Grodan Macro Plug Round with Slit, Bag of 50 Fifty (50) Grodan Rockwool Macro plugs, round with slit, 1.5" across Grodan Rockwool provides the perfect media for seedling or cutting root growth Macro plugs have a slit along the side that allows for easy insertion of cuttings Perfectly fits into the Grodan Gro-Block hole for easy transplanting Use with a tray with individual cells to ensure the macro plug stays closed around the cutting