This manual coffee grinder mill is made of durable and precise stainless steel burr core.It is faster and more effective than ceramic core,about 45 SECONDS for one time grind.VISIBLE GLASS CONTAINER-the capacity of burr coffee mill's GLASS CONTAINER is about 48G(0.1lb) COFFEE POWDER,the coffee grinder mill HOPPER can fill approx.20 g (0.04 lb) COFFEE BEAN (probably varies between coffee bean roasters)