A golf club head is characterized by stepped grooves in the striking face thereof. A first resistor is connected between a control electrode and any one of the pair of the main electrodes of the first field effect transistor, and a second resistor is connected between a control electrode and any one of the pair of the main electrodes of the second field effect transistor. The blue LED chip has a peak wavelength X slightly smaller than the peak wavelength Y of the phosphor such that when the light emitting device is subjected to a predetermined operating current, the phosphor decays due to thermal effect, and the LED chip has its emission spectrum red-shifted to substantially match with the excitation spectrum of the phosphor. At an extraction stage pure, aqueous solutions containing fluoro acid complexes of niobium and fluoroammonium complexes of tantalum are obtained. The carrier web can transport molded parts to subsequent process steps, such as coating, drying, inspection, curing, assembly or packaging.