An apparatus including a first circuit, a second circuit and a third circuit. A computer communications interface is configured to access via a computer network a training electronic media repository. Instead, direct application of the present invention to a bead of caulking compound sealant, or application via a finger or man-made tool, and subsequent smoothing with the finger or tool will allow correction of all imperfections in the caulking bead prior to curing. The impact resistance of the battery, the discharge characteristic thereof, the lifespan thereof, and others are very good. One side of the slot includes a protruded sidewall surface that protrudes into the slot toward an another sidewall surface of the slot. Different cells may operate asynchronously or with unknown timing.