1.Aluminium 2.[ACCURATE MEASUREMENTS]: Our aluminum adjustment blocks are all 3 inches long or 1/ 16, 3/ 32, 1/ 8, 5/ 32, 3/ 16, 7/ 32, 1/ 4. Inches, 5 inches long/ 16, 3/ 8, 7/ 8, 7/ 8. 16 15/ 32, 1/ 2, 23/ 32, 3/ 4, 1x2x3, combine rods to set 100 measurements. Stack adjustment bars for multiple variations or sizes, or use them individually for quick work and measurements. 3.[NO DAMAGE MEASUREMENT]: 15 aluminum construction, black anodized, much softer than the router bit, so the risk of damaging the carbide cutting is greatly reduced for better protection of router bits and saws. 4.[LASER ENGRAVED MARKS]: Easy to read and accurate engraved labels are engraved on the aluminum stand. You can quickly start working on your table without the guesswork and measurements. 5.[EASY TO USE]: Different size height adjustment blocks make it easy to adjust the height of fences, blades and other knives as needed, faster and more accurately than using a ruler.