This is a high quality Green ignition wire set for a Triumph Spitfire or MG Midget 1500. Your original ignition wires where green and these match that color perfectly. Overtime vibration can break the wire inside of the insulation, often at one of the connectors and will cause loss of spark or intermittent spark. Also as the wires age from heat and use the resistance of the wire will go up with age and this also will cause a weak spark. Last the insulation can break down, allowing leakage of spark energy to the engine block (ground) or other wires until rather than to the spark plug. Cross Reference 09045 09043.