Weapon Blender Airsoft have a ton of M4 airsoft guns in stock so rather than present to you one by one, they'll be showing it in two categories: the budget "Economy Line" and the higher budget/premium ones. They start with giving the Economy Line... "Our M-4 line is huge so we broke it into two videos the economy line and what we named the pro line. What's the difference? Internal construction and price. You get what you pay for my friends."