Reading Technologies Inc ED-2-4 Drain Electronic – 1/4"- 1/2"- Electronic timer drain, with indicator lights. Automatically drains water from tank. Solid brass ball valve with stainless strainer to protects valve. Reading Technologies, Inc. can solve most problems found within the compressed air industry.One of the most critical items in any air system that is often overlooked is a reliable drain mechanism on the main reservoir tank.The ED-2-4 drains automatically drain your tank as often as needed to provide water free air downstream. Use on any air reservoir tank, air/water separators, air filters, air dryers, or drip legs whenever condensed water removal is necessary. Reliance on a manually drained system often leads to water contamination of your critical air driven equipment or machinery.