Processes for the conversion, under conditions and with a catalyst system effective for olefin metathesis, of hydrocarbon feedstocks comprising butylene, for example all or a large proportion of a single C4 olefin isomer such as butene-1, are described. The second instant of time is within a predetermined time of the first instant of time. A portion of the final output frequency is coupled into the phase locked loop circuit that is phase locked to a reference signal from a crystal reference oscillator. At least the free end of the flexible transfer pipe includes a product handler for displacing the free end between a position for connection to the connection device and a disengaged position for storage. Moreover, such acoustic waves may be ultrasonic. An electronically-operated scale for use with a fishing rodreel that displays the line test value whenever percentages of that line test value is reached during reel drag setting, thereby also avoiding the need to conduct any calculations.