Jian ya na Antique Manual Cast Iron Coffee Grinder 1:The coffee grinder's base is made of pine, the body is built by cast iron. 2:You can easily adjust the powder's thickness. 3:It's British style oversized pulley that uses less power than other manual coffee mill. 4:Flap move up or down to adjust the powder's thinckness, please leave a 0.25mm gap to avoid an increase in friction or jammed.