CONCHAPAK (Sterile Water Reservoirs & Columns) Hudson RCI CONCHAPAK units are self-contained water and humidification cartridge systems used exclusively with the CONCHATHERM III, III Plus, and IV Heated Humidifiers. CONCHAPAK choices include three sizes of sterile water reservoirs and a choice of standard, low-compliance or minimal-compliance CONCHA-COLUMNs. Safe, reliable gravity-feed system provides uninterrupted water flow. Humidification is produced using the evaporative process to ensure minimal resistance to gas flow. Easy reservoir and column replacement. Minimal-compliance column incorporates one vertical and one 45-degree port. Columns are individually packaged, sterile, case quantities vary, see chart below.