Check the listing for details. Blast Cabinet Metering Valve: Harbor Freight Sandblaster Upgrade. Improve flow!. Condition: New. Listed at 49.94 USD. Upgrading your siphon tube abrasive blasting cabinet to a gravity assisted metering valve setup is one of the best mods you can make. Tired of surging, inconsistent media flow and struggling with a subpar siphon blast tube? This is the upgrade for you! This durable, affordable DIY abrasive blast cabinet metering valve allows you to upgrade at a great price The metal construction and easy to use full 3/8” air inlet valve offer significant improvement over the bad stock siphon tube design. A drain plug allows easy media changes. Features: easy install instructions provided. Beveled internal edges for better flow at hose connection. Rust preventative coating. Sealed threads. Use 1/2" ID blast hose.(Customizable) Easy toolless adjustment. Click or tap “See full description” below for more info.