Size 001 = 0.5 inches (13mm) deep by 1.5 inches (37 mm) in diameter over the coils. Intended for light-duty machines with up to 0.5 inch drilling capacity.
Size 002 = 0.75 inches deep (19 mm) by 2.45 inches (62 mm) in diameter over the coils
A much heavier spring for drills and millers with a 1-inch drilling capacity
