Printing
I've printed these grips successfully in Hatchbox Woodfill PLA, Overture PETG, and CarbonX CF-Nylon. 
For best results, print horizontal with the inner face of the grips down, and supports everywhere 
(and if your slicer has an option for "don't support bridges" turn it off).

Compatibility
These grips are compatible with Rock Island Armory's 1911A2 variants, and swapping them out
should require very little, if any, modification. 
They're not designed for Para/Remington double stack 1911s, but may be close enough to fit with very minor modifications.
They are not compatible with STI 2011s.