Quietsource generators from Generac combine a powerful lower-speed standby generator with Generac's exclusive Whisper-Test feature. Quietsource models operate at 1800 rpm for lower noise. Generators with Whisper-test exercise at a slower speed, producing less noise, when running for weekly exercise. This feature allows your generator to remain ready for fast response without drawing the attention of your family and neighbors. All QT models can be used with Generac transfer switches or with competitor's switches utilizing two-wire start contacts.