An Erosion Control Sock is an expandable filter material in the shape of a tube typically filled with wood chips, compost, or other mulch. This can be a superior alternative to silt fences to divert, control and trap sediment and debris during construction activities. Erosion control socks allow water to flow through, while keeping soil in place. Socks can be biodegradable and are available in a variety of diameters. Erosion control socks are filled on-site pneumatically with the use of blower trucks.