Maytronics Dolphin™ 9999399X-BL4 PROX 2 Robotic Pool Cleaner with Caddy and Remote. The Dolphin PROX 2 provides highly efficient pool cleaning for hotel, campground and school pools that are 15-25m in length. The advanced gyroscope system ensures accurate scanning for systematic coverage of floor, walls and water-line. High-capacity, ultra-fine pool filtration captures all dirt, dust and other debris, leaving clean and hygienic water throughout.