Zen-On Bass Recorder 5400B Maple Maintenance completed by the manufacturer in August 2023. Purchased as a used item in July 2023, and had it maintained by Zen-On via Yamaha in August 2023. During the maintenance, 4 key pads were replaced, the block was cleaned, and the intonation was adjusted. The maintenance fee was 17,600 yen (including tax). The genuine Zen-On strap is a new, unused item purchased in October 2025. As shown in image 10, there is a slight dent in the windway, but it does not affect the performance. Used in a recorder ensemble about twice a month until September 2025, but was put up for sale after switching to a Zen-On Pastoral in October 2025. I previously owned a Yamaha YRB-42, but the Zen-On bass recorder has a greater volume and richer resonance compared to the Yamaha. The pitch is a bit high, so I was playing with the head joint slightly pulled out in the ensemble. A recorder instructor who graduated from a music university also said that the Zen-On bass recorders all tend to have a high pitch, and the newly purchased Pastoral also has a slightly high pitch, so I play it with the head joint slightly pulled out. This item has been stored at home by an individual, so please purchase only if you understand this.