Our massage guns battery lasts 4 hours per charge (roughly 3–6 hours of actual use time depending on speed setting), and takes only about 3o minutes to fully recharge via USB-C.

No the massage gun is very quiet on every speed

Inhale/exhale through the mouthpiece against adjustable resistance, a few minutes a day, gradually increasing resistance levels as strength builds.

Yes, you can completely limit or maximize the level you want to train at.