This is a non-pressurer for French horn. Those who intend to use this device probably understand its features, so I will refrain from explaining them. Many of the commonly available models have a long body, but this is a shorter version, making it a bit easier to hold. Spare springs are also included. It wasn't used for very long, but there is some evidence of use, so please understand. It was sold at a certain musical instrument store for 13,200 yen.