299,050 is the number for the Littelfuse product series, known as SPF1, which are fast-acting, compact semiconductor fuses used to protect sensitive circuits from high inrush currents and short-circuit conditions. These fuses are available with a variety of amp ratings, breaking capacities, and hold current values, as well as a variety of form factors and mounting configurations, including Axial Leaded, PCB, and SMD designs. They are also relatively inexpensive and are ideal for a variety of applications, including automotive, consumer products, industrial, and communications.