COARSE GRADE: Our Feather-Lite is manufactured to our specifications by Growstone. We were really excited to find another great drainage product that has even more terrific benefits than our famous Terra-Lite. Feather-Lite is so named because it is incredibly lightweight! This makes it especially ideal for those really big tanks that even Terra-Lite can get heavy in. Additionally, it is exceptionally porous holding many times it's weight in water. It is larger is size overall with pieces ranging from 1.5" or so to 1/2" in diameter. One of the other great features of this product is that it is made from 100% recycled glass making it a very "green" product! We have been trialing this new product for a while now and are thrilled with the results. It has worked out great in terrariums ranging from 12" square through 125 Gallons. Qty sufficient to cover the bottom of a 20 Gal Reg tank ~1.5" deep.