T-Shank Jigsaw Blade Set includes 3 kinds of blades: 6, 10 and 18 TPI (teeth per inch). 6 TPI and 10 TPI blades are 4" long and made with high carbon steel material. 18 TPI blades are 3" long and made with bi-metal material. Blades feature regular and fastcut type of teeth. T-shank design fits all Bosch and DeWalt jigsaws. Includes 2-sided case.