GC_UPC Glock G21 Gen 4 45 ACP 13+1 W/ Tritium Night Sight & Three Mags - Police Trade-In $429.00 - show more like this 14.95 The Castle Arms GC_UPC Glock 21 Gen 4 45 Auto 3-13 rd Mags UG2150203 $599.00 UG2150203 show more like this 9.99-29.99 Per Item Gunprime