This high-quality, 3-1/2" diameter rubber cone tree sprue base (CT-style) is ideal for creating a stable and secure base for your molds. Its cone-shaped design allows for easy removal of cast parts, while the rubber construction provides excellent vibration dampening. Perfect for use with a variety of casting materials, this sprue base is a versatile tool for any casting application. Leak-proof, and will fit both regular and perforated flasks. Great for Centrifugal casting and vacuum lost wax casting processes; made from natural rubber materials, and holds 5/16" - 3/8" tree tightly into place.