The HR3SM4 from Micross is a Space Qualified Diode with Dynamic Resistance 4 to 47 Degree C/W (Thermal), Forward Current 3 to 5 A, Forward Voltage 1 V, Reverse Current 1 to 60 uA, Reverse Voltage 400 V. Tags: Axial-Lead. More details for HR3SM4 can be seen below.