Hello, thanks for checking out my custom Glock Frame! this frame uses DD17.2 Glock 17 rail inserts and a gen 5 slide lock spring. 

There are 4 versions in this pack, they are as follows;

GXL17 - Standard G17 frame without a rail
GXLR17 - G17 Frame with a rail
GXL34 - G34 length frame without a rail
GXLR34 - G34 length with a rail

I recommend printing with at least 8 walls minimum, 100% infill, using PLA+ or tougher. 
Rails down, it is designed for rails down, printing it any other way will get you blocked and reported to the authorities >:(

Questions? Comments? Concerns? Find me on Twatter!