The ultimate white noise machine with patent pending white noise generation technology that provides 10 different white noise sound options for perfect tone selection. White noise is a natural, clinically proven sound that helps people (and animals) sleep better. Perfect for improving sleep, blocking noise, managing tinnitus, dorms, baby"s room. 10 unique white noise sound tracks suit your personal preference. Play music from iphone/ipod/mp3. Power by outlet or pc. Product features: 4 position auto off timer - 30, 60, 90 min. Plus continuous play; rotary volume control; replay button plays last sound, timer and volume selection; headphone/pillow speaker jack; iphone/ipod/mobile device input jack allows use of s-100 as a speaker; powered by micro usb adapter allowing you to power unit from laptop, pc or wall outlet for portability and versatility; perfect for dorms, travel or home; big 3 inch speaker for high quality sound; compact size (4.62 x 4.25 x 2.25 inch/11. 7 x 10. 7 x 5.6 cm) is ideal for home or travel; super energy efficient - keep it running day and night as it consumes less than 1% of the electricity of traditional white noise machines. One size.