& & The portable white noise sound machine is small enough to fit in your hand. If you travel and lug around a travel sound machine, this is a very good alternative comes with favorable features: compact size, rechargeable battery, headphone jack, lanyard for hanging anywhere, 21 non-looping sounds, customized timers, 32 volume levels, and even memory functions The travel white noise machine can be used both rechargeable( up to 50 hours (Medium Voice)on a single charge) and plugged in, and it also has a 3.5mm headphone jack so that you can use and enjoy it outdoor or airphone. Comes with a USB-C cord to charge & Including white noise, pink noise, brown noise, fan sounds, and nature sounds like thunderstorm, campfire, bird chirp, cricket chirp, ocean wave, meditation, 3 lullaby, shush, fetal, waterfall, examination hall, bustling city, brook. This white noise machine promotes deep sleep and satisfying daily relaxation needs This has 32 levels of volume, which can loud enough helps block disruptive environmental noises, help you improve sleep, focus on, office privacy, and meditation, perfer for home, office or travel - & As a sleep sound machine ,it has 30/60/90minutes and 8hours auto-off timer or continuously play setting. After you set the volume grade, timer and music, the noise maker will memorize your preference. Every time when you restart it, it will recover your favorite setting