Toda Racing campulleys allow precise tuning of camshaft timing. Adjustable campulleys are essential when using Toda camshafts or any non-stock performance camshaft. Toda Racing uses 7075 aluminum to produce their campulleys while our competitors use 6061.The use of 7075 aluminum allows Toda Racing to offer the strongest and lightest campulley on the market. For long term durability the timing marks are machined into the metal, not painted on, etched, or silk screened, therefore they will not rub off with age. Sold by the pair.