Historical clue formulations

• Part of a heart or faucet — 2026-09-23
• Device on a duct — 2024-01-16
• Key for a trumpet — 2022-03-18
• On/off device — 2021-02-22
• One of four in the human heart — 2021-02-10
• Gas regulator — 2015-09-17
• Pipe attachment — 2006-02-21
• Spigot, essentially — 2002-09-12
• Trumpet feature — 2002-09-03
• Pipe feature — 2002-01-23
• Water regulator — 1995-10-29
• Escape facilitator — 1995-08-25