Ceramic Rock Slides have an ultra hard/smooth finish similar to glass but produce more sustain and low end since they outweigh the glass, and even our brass slides. They’re far more durable than glass being made out of high heat industrial ceramic rather than typical coffee mug style studio clay. Hi-tech injection moulding gives you the same tapered interior and other Rock Slide features you’ve come to love on the other models. Medium, Ring Size 9.5. Length, 2.36". Internal Diameter, 0.76", Thickness. 3mm.