Box Gutter

A Box Gutter is a rain gutter on a roof usually rectangular in shape; it may be lined with metal, asphalt or roofing felt, and may be concealed behind eaves or in a roof valley. Box gutters are essentially placed between parallel surfaces, as in a valley between parallel roofs or at the junction of a roof. They should not be confused with valley gutters or valley flashings which occur at non-parallel intersection of roof surfaces.

WIKIPEDIA ENTRY FOR BOX GUTTER