Double Edge : snap throw A method of throwing a salvage cover which is similar to the single edge snap throw; however, it is designed to cover two relatively narrow objects that are close to each other. See also: Single Edge Snap Throw
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}