Thunder Rods provide the ultimate in strength and durability, ideal for the heaviest of hitters. Made of premium select birch dowels, these rods provide an excellent consistency and feel.Seven extra large premium select birch dowels. Diameter: .675″ Length: 16″. Smooth grip for easy playability. Unique wrap near the neck provides a tight sound with just enough texture and improves durability. All Promark drumsticks are designed, engineered, and manufactured in the USA at our Texas facility to the most stringent quality controls in the industry.