Rexius medium grade fir bark is the only bark which is heated to 375 degrees Fahrenheit for 30 minutes to completely destroy fungi, bacteria, insects and snails. Presoak for 24 hours before use as this material is very dry. This size is best for plants in 4 inch pots or larger. Great for Paphs, Cattleyas, Vandas or Phalaenopsis. The particle size is from 3/4 to 1" . The best bark around! Approx. FedEx Ground shipping on 1 bag: $15-25, 2 bags: $35+, depending on region.