and age of those who will use them, and the available space. In schools and cricket clubs where use will be high, construction will be tailored to that. The nets may also need safeguards against misuse or vandalism. Therefore, the frame is often constructed out of heavy-duty galvanised steel tube with an overall diameter ranging from 34 to 50 mm. The tube is then joined by key-clamp brackets. This system requires permanent concrete ground sockets, but the actual frame of the cage can still be dismantled and removed. Outdoor nets can be fitted with wheels to be completely mobile. There are variations in the design of outdoor nets such as use of pulley system where the netting is mounted on a cable that spans posts located at either end. Garden nets are frequently home-made, often to a professional design with locally sourced components. This saves money, and cricket nets have a simple design and purpose, so are not difficult to make. Nets should be no less than 9 ft wide, with 12 ft being optimum. If the nets are under 24 ft long, they should be at least 9 ft high; if under 36 ft long, at least 10 ft high; and 12 ft high if longer than that. This prevents balls ending up on the roof of the nets when bowled. The length is less critical, but the longer the safer. Netting Netting is the most important component. The netting twine is usually made of a synthetic polymer such as polyethylene, which is hardwearing and relatively cheap. Before about 1995, nets were often made from nylon, but this became too expensive. Nets are often black, green or white. The mesh gap is usually 50 mm and the twine will commonly have a diameter of 1.8 to 3.0 mm. Netting may be knotless or knotted: knotted is considered superior. The breaking strength of knotted netting is higher for the same diameter twine. Good twine will be UV stabilized and rot proof. For home-made nets, netting is the only specialist supply. Netting is seamed at its edges to prevent fraying. The seam is usually a 6 mm cord sewn into the netting where it meets a cage or end. Canvas blinkers can be added to offer privacy and to reduce wear. Also, partial canvas skirts of 0.5 m can be added to the bottom to prevent damage from wild animals. In