The 1N58xx is a series of medium power, fast, low voltage Schottky diodes, which consists of part number numbers 1N5817 through 1N5825.
[2][3][4] The 1N581x are typically packaged in the DO-41 axial through-hole case, and in many cases are interchangeable with the 1N4001 series.
Being Schottky diodes, the 1N58xx parts have roughly half the forward voltage drop of the 1N400x/1N540x series diodes, which improves efficiency in applications where they are usually forward-biased, such as power converters.
The cost is a lower voltage rating and higher reverse leakage current (approximately 1 mA at room temperature and increasing with temperature).
Common surface-mount relatives of the 1N58xx series are the SS1x and SS3x series, such as the SS14 (1 ampere) and SS34 (3 ampere) surface-mount parts.