The MasonMate Rubber Nuts have a brass insert. Can be used in virtually any construction material. Ideal for use in damp and sanitary conditions.Select Option M10 x 55mm (50)M12 x 75mm (50)M4 x 11mm (50)M4 x 25mm (50)M5 x 15mm (50)M5 x 25mm (50)M6 x 15mm (50)M6 x 25mm (50)M8 x 25mm (50)M8 x 50mm (50) Add to Basket Quantity