This is our one piece "Taco style" inside the waistband magazine holster. They could me equipped with an Manual Retention Device (MRD) that allow you to interchange different sized magazine. The double stack will accommodate all 9/40 single and double stack magazines. The single stack will accommodate single stack only. It's made with .08 thick kydex for a durable perfect fit. Please allow 10 to 15 business days lead time.