Best Value Vacs TRS21 Active Closed Loop Recovery KitThe TRS21 Active Closed Loop Recovery Kit The TRS21 Active Closed Loop Recovery Kit is an upgrade kit that can be added to our passive systems to make it active. An active kit has the added benefit of a recovery pump, which enhances the movement of solvent vapors by adding a push pull action on top of pressure manipulation through temperature. The addition of the pump increases the efficiency of the recovery process and requires less dry ice. For