The Valken M4 Magazine Style Speed Loader is an airsoft BB speed loader that is required to load BBs into airsoft mid-cap magazines and low-cap magazines. This particular speed loader also has a built-in flip over gas-magazine feed ramp/adapter for easier loading of gas pistol and gas rifle magazines. This airsoft BB loader is made with durable, high strength polymer construction and a translucent body allowing you to see how many BBs are remaining. They hold 400 BBs, and are specifically designed to fit inside a single M4 magazine pouch. The o-ring in the feeding channel prevents BBs from falling out, and the agitating plunger reduces the frequency of jams and blockages. We recommend our Valken Accelerate ProMatch BBs when using this speed loader.