The shur-lock snap for easier and faster method of connecting tackle products to and from the fishing line, a straight arm connecting to a proximate arm, the proximate arm furthermore connected to an opposite arm where the distal end of the opposite arm is at least once wrapped loosely indirectly surrounding the straight arm. Two sides of one end of the plastic main body being respectively formed with two guide pins. The latching strike is pivotable between open and closed positions for releasing and retaining a latch bolt respectively. Relative to the front surface, at least a portion of the first material is located on top of and overlaps at least a portion of the second. The plurality of first reference voltages are alternately compared with the sense voltage. In some examples, the system, via an inverter, injects a frequency disturbance to a location of the utility grid associated with a DG generator, measures both the frequency error due to the disturbance and the frequency drift of the location of the utility grid, and determines islanding based on a maximum value of the frequencies.