The Rock Slide CRS-MP moulded Ceramic Pacific; molded ceramic slide; dimensions: 19,5 x 49 mm; inner diameter: 19,5 mm; ring size: 9-11; wall thickness: 3mm Regular; material: ceramic, pacific dark blue; the molded ceramic version has a very hard surface like glass, but produces more low end and sustain, as they are heavier than the glass or brass Rock slides