SkimLite EliptLock Blue Durapro Dual Lock Series P/N: 3500 It's dual locking system combines the outside lock from the 5000 Series and the EliptiLock internal lock from the 3000 Series. The dual locking system ensures that the pole stays locked even during the most demanding jobs. The outside tube is made with blue anodized, heavy-drawn tubing; the inside tube is made with satin-clear anodized, heavy-drawn tubing. Comes with a large drain hole.