height as the inner wall or may be machined later to reduce height if desired or may be molded with the desired height without later machining the height of the panels 3 may similarly be reduced openings 6 between the panels and the walls may be triangular rectangular or of other polygon shapes string holes 7 may be made in outer and inner walls and in panels if needed to pass strings sufficient amounts of the panel wall material to form fillets may be molded along with the connections of the panels to the walls distance between the two walls 9 may be varied along the length of the circumference of the frame fig1 b shows the same frame as 1a except the panels are approximately perpendicular to the walls and are not interconnected to each other holes 7 may be passed through the interior of the panels so as not to expose the strings this will reduce air resistance caused by the portions of the strings between the inner and outer walls frames as in fig1 a and 1b are preferred when all structural regions of the entire frame from the head to the core of the handle are of the similar design intent and the entire frame can be made by extrusion as a single piece fig2 shows another preferred frame shape panels 10 connect inner and outer walls 11 and 12 and openings 13 may be of the shape of any polygon here the walls 11 and 12 which define the spaces 13 therebetween are not of constant thickness along the.