The brails, or purse lines, consist of heavy monofilament and run from the lead line to a terminal point at the swivel on the end of the hand line. Usually the brails measure slightly longer than the length of the net.
 
The lead line, or hang line, is one of the most important pieces of the whole cast-net puzzle. On better nets, the lead line usually consists of large-bore egg sinkers affixed to a rope that runs around the circumference of the net. The leads are usually whip-stitched in place by monofilament or nylon cord.
 
Better nets usually weigh 1 to 1 1/2 pounds per foot of diameter. For example, a 12-foot net should weigh from 24 to 36 pounds. This weight can be altered on custom nets to account for deep- or shallow-water conditions. At one time, my grandfather experimented with the kind of integrated-lead lines often used on large commercial seines. On this setup, the lead was actually fixed inside the rope used to create the lead line. These nets were less prone to snag on the bottom, but more importantly, they guarded a boat's gelcoat and fiberglass from unwanted nicks, dings and scratches. I don't know of anybody commercially producing integrated-lead-line nets, but if you're having a custom net built, it would be worth investigating.

Mesh Size and Material
Consider several factors when choosing mesh size. First, the span of the mesh should be small enough to prevent gilling or damaging the scales of your primary target species during capture. Secondly, mesh size determines the sink rate of the net. Larger mesh offers less water resistance, so the net sinks faster. This is especially important when targeting fast-running species like ballyhoo, herring or pilchards in water as deep as 30 feet.
 
The low cost and widespread availability of monofilament makes it the preferred mat-erial for constructing cast nets these days. It's also easier to repair than braided nylon and doesn't retain water between throws.
 
 Manufacturers use varying strengths of monofilament for nets of different mesh sizes. For small mesh sizes, such as 3/16-inch, mono as light as 4-pound-test proves adequate. Since anglers use large-mesh nets to catch big, strong baits, a 1 1/4-inch net may be made from 20-pound or heavier material.