Features: * Made of high quality material, durable * Made from molten rock, spun into marshmallow fibers, then compressed into cubes. * After high temperature treatment, it is non-toxic and sterile. * Small bulk density, light texture, large porosity. * Good air permeability, strong water absorption and good drainage. * Suitable for growing and establishing all types of plants. * Excellent choice for soilless cultivation. Specification: * Material: cotton * Color: as picture shown * Size: 25*25*25mm,30*30*40mm, 40*40*40mm Package Included（optional）: A:50pcs 25*25*25mm ROCKWOOL B:36pcs 30*30*40mm ROCKWOOL C:21pcs 40*40*40mm ROCKWOOL Note: 1. The real color of the item may be slightly different from the pictures shown on website caused by many factors such as brightness of your monitor and light brightness. 2. Please allow slight manual measurement deviation for the data. Made of high quality material, durable Made from molten rock, spun into marshmallow fibers, then compressed into cubes. After high temperature treatment, it is non-toxic and sterile. Small bulk density, light texture, large porosity. Good air permeability, strong water absorption and good drainage.