on a bike, in order to get grip shift, or twist shift, do i need a SRAM rear

[secretmidgetman]

derailuer? i want to change my shifters to grip shift, or "twist shift". And i read somewhere that you need a SRAM rear derailluer to get grip shift. But my friend is a super bike mechanic, and he told me that you dont need a SRAM rear derailluer to get grip shift. is that true?