Made of clear glass, with smooth polished edge. Bottom 4 rubber feet prevent them from slipping. Heat-resistant, can well protect your tables. 3 1/2″x 3 1/2″, thickness 4mm. Crystal color grace and elegant, suit used in high-end place, coffee tables, restaurants, hotel or business office or family kitchen dining tables. With your company name or logo, Great gift for you next event. Price for square corner, besides rounded corner or 10mm thickness also available.