Made of select kiln-dried mahogany finished with 2 protective coats of clear, hand-rubbed lacquer. Edges are guarded by double-angle screwless brass bindings. Rubber end-caps are screwed on for better shock-absorption and durability. 2 clear curved vialsper sight, each solid-set by hand. Heavy glass lenses protect all vials with a water-tight seal. 18" through 28" sizes have hand grips, remaining sizes feature convenient hand holes. 1-3/16" x 2-7/16" frame.