The Sound Oasis White Noise Sound Card (SC 250 05) provides an ideal selection of different white noise sounds to help promote sleep and relaxation. Simply insert the card into your Sound Oasis to enjoy these 6 additional sounds! NOTE: This is an accessory ONLY for use with Sound Oasis Series 550 and 560 Sleep Sound Therapy Systems. Great accessory for item 600993. Sounds Included: White Noise: Comprises consistent sound containing equal amounts of high and low pitch sound frequencies Pink Noise: Consistent sound containing more low pitch sound frequencies than higher frequencies. Pink Noise has more bass (low frequency) sound than White Noise Brown Noise: Consistent sound containing more low pitch sound frequencies than higher Gray Noise: Consistent sound containing equal amounts of high and low pitch sound frequencies. Compensates for the human ear sounds the same at all frequencies White Rain: A rain shower combined with white noise White Stream: A mountain stream combined with white noise