The HPA 1/4 Slip Fitting Elbow Adapter is a right 90 degree part that attaches to your engine's rubber macro line. A replacement part. Male ends attach to QD adapter sold separately. The plastic/rubber end slips onto your macro line for a pressurized seal. This is not the 6mm size, but will work fine with 6mm macro line once pressurized. 1/4" plastic end to male 1/8" male end HPA adapter, with 90 degree turn. Instead of your line going straight down, out of your gun, this angles the air line back to your tank.If you lose the one that came with your Polarstar engine, this is a drop-in replacement.