The Nautilus by Stebel. The internationally patented Stebel Nautilus air horn features space-saving engineering not known to be offered by any other manufacturer in the world. The compressor and trumpets are integrated into a self-contained unit. Durability is another feature, as is the excellent sound generated by the horn. The unit is 4.5" X 4.5" X 3". Availabe in Black or ABS Chrome. In-house limited warranty.