Best Value Vacs 8.5 lb Athena Bi-Directional Closed Loop Extractor8. 5 lb Athena Bi Directional Closed Loop Extractor The 8. 5 lb Bi Directional rack has the same function as the stand alone bi flow, but with the convenience of a rack mounting system. By using a bottom flood on the first wash to ensure all material has seen solvent, preventing channeling through the material. Finish the run with a top flood input to ensure all residuals have been washed from the material. Oil bearing solvent is collected in the