M2 Armament Group DIY Polymer80 PF940v2/G17 Rail Set w/ Locking Block/ Rear Rail Module/ 2x Pins Black. Engineered specifically for the growing community of home gunsmiths 80percent builders and 3D printing enthusiasts (3DP / FMDA / PY2F) this essential steel rail kit delivers the critical structural components required for smooth slide cycling rigid lockup and flawless frame function. Specifications for M2 Armament Group DIY Polymer80 PF940v2/G17 Rail Set w/ Locking Block/ Rear Rail Module/ 2x Pins: Manufacturer: M2 Armament Group Color: Black Package Contents: M2 Armament Group DIY Polymer80 PF940v2/G17 Rail Set w/ Locking Block/ Rear Rail Module/ 2x Pins M2 Armament Group M2-AGFRDC-BAR-SILVER: DIY Polymer80 PF940v2/G17 Rail Set w/ Locking Block/ Rear Rail Module/ 2x Pins Black