Abstract: A lens cover for an optical instrument has a first flexible cover panel having a sleeve thereon forming a substantially closed loop, and a second flexible cover panel having a sleeve thereon forming a substantially closed loop. A drawstring has its first end secured to the first flexible cover panel, with the portion of the drawstring adjacent the first end extending through the sleeve on the first flexible cover; and its second end secured to the second flexible cover panel, with the portion of the drawstring adjacent the second end extending through the sleeve on the second flexible cover.

Abstract: A lens cover for an optical instrument has a first flexible cover panel having a sleeve thereon forming a substantially closed loop, and a second flexible cover panel having a sleeve thereon forming a substantially closed loop. A drawstring has its first end secured to the first flexible cover panel, with the portion of the drawstring adjacent the first end extending through the sleeve on the first flexible cover; and its second end secured to the second flexible cover panel, with the portion of the drawstring adjacent the second end extending through the sleeve on the second flexible cover.

Abstract: A spark plug with lower operating temperature has an electrode with a tip which evenly distributes heat imparted to the firing end portion of the spark plug. The electrical insulating material surrounding the electrode is spaced at a predetermined distance from the firing end portion of the spark plug to allow the heat to more quickly travel away from the firing end portion. An annular groove in the first end surface of the electrical insulating material minimizes electrical surface discharge between the electrode and the annular metal shell of the spark plug. Radii at locations of change in cross-section in the bore of the annular metal shell and the electrical insulating material serve to minimize voltage breakdown.

Abstract: A spark ignition system of an internal combustion engine has a plurality of electrodes operating at high voltages to produce a plurality of sparks across the combustion zone. The construction of the system permits the formation of long length sparks while substantially maintain the utilization of customary electrical wiring sizes.