Starrett 666-1 is a 666 Series thickness gage or "feeler" stock of 25-ft (7.6 metre) length and 0.001 inch thickness. It is marked at every 6 inches (150 mm) with a line to snip off the desired length without any wastage.
It is made of tempered steel and is widely used for cutting off the required length for adjusting tappets, spark plugs and distributor points; checking bearing clearances; fitting pistons, rings and pins; and gaging narrow slots.
