# Region render matrix via master in Reaper From the render window, select "Region render matrix via master" from the "Source" drop-down.[^1] This is great for sending instrumentals to clients. [^1]: [What's New in REAPER 6.59 - region render matrix via master and more - YouTube](https://youtu.be/yywlIEgKvaw?si=FDtKKyV9KDtxBJSO)