The DeWalt DW3705-5 is a pack of 5 4" 8 TPI U-Shank Aluminum/Fiberglass Cobalt Steel Jig Saw Blades. The blades have reinforced teeth design which protects the teeth from damage and stays sharper longer. The side chip path helps to quickly remove debris and clear the channel for cleaner and smoother cuts. The cobalt steel (bi-metal) lasts up to 5X longer than standard blades.