<https://kleinn.com/products/model-310-manual-pull-chain-air-valve#product>
<http://schema.org/description>
"Pull Chain Air Valve for Roof Mount Air Horns \tHand pull lanyard valve \tFor roof-mount horns \tInlet: 1/4\" O.D. tube \tOutlet: 1/4\" O.D. tube\n"
<https://kleinn.com/collections/accessories/products/model-310-manual-pull-chain-air-valve>