These are Large Scale Control Horns from Great Planes. FEATURES: Glass-filled for extra strength in giant scale or large sport-scale applications. A larger base provides more mounting stability Mounting hardware is included Control horn has 5-holes for different control throws INCLUDES: Two Large Scale Control Horns Two Control Horn Mounting Bases Eight 4-40 socket head cap screws REQUIRES: 3/32"-hex head wrench to tighteh 4-40 cap head screws. 1/8"(3mm) Drill bit, to drill holes in mounting plate. SPECS: 4-40-Screw Length-(34.1mm) (1.346")-Thread Only-(23.7mm) (.935") Base Length-------(25.1mm) (.988") Base width at widest point-(24.2mm) (.954") Control horn at highest point from bottom of base-(34.1mm) (1.346") COMMENTS: Mounting Template on back of header card in package JCT 10/09/01 ir/kh