The Sig Sauer M18 ProForce 6mm 21rd BB Green Gas Magazine with Black Base Plate is a high-performance magazine designed for the ProForce M18 airsoft pistol. This magazine holds 21 rounds of 6mm BBs and is powered by green gas, ensuring smooth and reliable operation. The high-tension internal steel spring provides rapid BB feeding, minimizing the risk of jams and enhancing your shooting experience. Constructed from a durable metal alloy, this magazine can withstand high-impact drops and offers a realistic weight, making it ideal for training scenarios. The black base plate adds a sleek touch to the overall design, ensuring it complements the look of your airsoft pistol.