A custom job on a Hi-Capa 5.1 Pistol which you can get right now from RedWolf Airsoft... "Having problem to find an accurate, reliable gas blow back pistol? Don't like the plastic slide on the stock Marui? Want a out of the box, skirmish ready side arm? Get this RWC OPS Hi-Capa 5.1 GBB pistol!  RWC OPS Hi-Capa 5.1 (Two-Tone), based on a Tokyo Marui GBB hi capa 5.1. Modified by our gas blow back expert, it's able to use Top Gas and Green Gas, Upgraded with an Airsoft Surgeon CNC aluminum slide, it will last for a long time. Skirmish ready, shooting at 300fps with 0.2g BB, top gas, it's a very perfect weapon for CQB.

Apart from the slide, other internals are stock Marui, so you may also look at other upgrades like: PDI 6.01 Precision Inner Barrel for Marui Hi-Capa 5.1; Airsoft Surgeon Nozzle and Piston Head Kit; Nine Ball Wide Use Air Seal Hop Up Rubber Chamber for Marui VSR-10/G17/G18/Hi Capa/P226 and other Marui Handguns; PDI Recoil Spring (Hard Kick) for Marui Hi-Capa 5.1."