The "VORSK 13 V-Rail System & Barrel Nut VMP-2M Grey NO BARREL NUT" refers to 
a specific grey, 13-inch M-LOK handguard designed for the VORSK VMP-2M Gas Blowback Airsoft Rifle, sold without the crucial barrel nut needed for installation, meaning you'd need to source that separately, likely from other Vorsk VMP-2 parts listings. It's a modular, tactical rail system with a Picatinny top rail and M-LOK slots for accessories, offering customization for your Vorsk airsoft rifle. 
Key Details:
Product: VORSK 13" V-Rail System (Handguard).
Color: Grey.
Compatibility: Specifically for the VORSK VMP-2M GBB Airsoft Rifle platform.
Key Feature: "NO BARREL NUT" means this listing excludes the necessary barrel nut for attachment, so be aware you'll need to buy one.
Design: Features M-LOK on the sides and a full-length Picatinny rail on top for accessories.