Sounds, Patches and the Browser : About ReFills

About ReFills
A ReFill is kind of a content package for Reason Essentials and Reason, which can contain sounds and effects patches, samples, REX files, SoundFonts and demo songs. If you like, you can compare ReFills to ROM cards for a hardware synthesizer. On your computer, ReFills appear as large files with the extension “.rfl”.
All sounds included with Reason Essentials are embedded in a ReFill named “Factory Sound Bank which was copied to the hard disk during installation.
Additional Propellerhead ReFills are available for purchase. You can also download ReFills from other Reason Essentials users on the Internet, purchase them from other sample manufacturers, etc.
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In Reason Essentials, you can use the browser to list and access the embedded sounds and other components within the ReFills, just as if the ReFills were folders on your hard disk.
Furthermore, if a song makes use of components from ReFills, Reason Essentials will tell you which ReFills are required.

Sounds, Patches and the Browser : About ReFills