Rexius large 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. We aren't always able to offer the large sized bark as it is not always available. Large particle size from 3/4 of an inch to 1-1/2 half inch. Best used for specimen plants of Cattleya and Laelia species as well as for Vandas. Approx. FedEx Ground shipping for 1 bag: $15-25+, 2 bags: $35+, depending on region.