The 5701 can be used in place of the standard trumpet on GFB valves (Part numbers T9003 & T9503), and will make a whistling sound. However, it is necessary to run the valve so that all (or most) of the air vents through the trumpet ? Respons valves will typically not generate the velocity required to whistle when set to 50/50 venting.
XMAS BREAK LAST SHIP DATE 18 DECEMBER
📦All new orders placed after that date will be shipped once we return on the 5th January 2026
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