Amazon.com: Sleep and Relaxation Sounds: Alexa Skills

By default, the sounds will loop automatically and play until you say “Alexa, Stop”. To limit the time that the sound will play, first play the sound using one of the above methods and then say “Alexa, set a sleep timer for 2 hours” or whatever time limit you would like. NEW FEATURES: Now Featuring Guided Sleep! Just open the skill and say …

https://www.amazon.com/Voice-Apps-LLC-Relaxation-Sounds/dp/B06XBXR97N