A putter club head is provided with an elongate cavity communicating to the exterior through a rectangular opening in the striking face thereof spaced above the club head lower surface so that the portion of the club head between the cavity opening and the lower surface forms a lower shielding structure to deflect any plant growth in the path of a putting stroke. The single-hand-held, single-hand-operated device includes a housing having a handle portion that is selectively collapsed to generate a propellant pulse that is conveyed into and through powder stored in a reservoir mounted at an upward angle to the horizontal in a receptacle provided in the housing. During the first speech detection mode, the computing device compares detected speech to the activation phrases to identify any potential matches. Ceramic tile insulation may be applied in two layers with the material properties of the two layers being different, and with the gaps of the two layers being misaligned. A light section can emit light with arbitrary illuminance. A first distance to a first measuring point and a second distance to a second measuring point are determined.