5 Gallon metallic exchange cartridges meet most low volume and special silver recovery needs. Can be used as a primary silver recovery method in a small lab or as a secondary (tailing) treatment to an electrolytic system. Two exchange cartridges are recommended to help comply with most discharge regulations. instructions included. Silver Bearing Solution is metered from the trickle tank (ball valve adjustable) to your Minilab/Loon Silver Bucket. Silver collection bucket sold separately (bottom bucket).