Miniature air dielectric variable like E.F. Johnson "160 series" model 160-107. Capacitance range 2.1-14.6 pf. 15 plates total with .017" air gap. Mounting face is .75" high x .625" wide. .25" mounting hole. .5" overall shaft length from face, with 3/16" diameter shaft .25" long for adjustment. Overall length is 1.5".