Fiber reinforced silicone matrix resin based composites are made more resistant to delamination by incorporating a suitably tough, lower modulus silicone resin, different from said matrix resin, between each fiber layer of the composite. The body structure includes an overlay material surrounding the cavity, and includes a metal substrate surrounding the overlay material. The transmissive-electron-multiplier foils also mitigate both space charge expansion and improve beam propagation effects, by shorting of the radially directed electric field at the axial location of the foil. The guide bar may be configured to guide a golfer’s backswing such that the swing begins in a desired swing plane. In addition, conductive vias are also formed to electrically connect the conductive vias of the second conductive plane to their corresponding redistributed bond pads in the first conductive plane.