The JAN1N6643 from Micross is a Space Qualified Diode with Forward Current 0.3 A, Forward Voltage 0.8 to 1.2 V, Reverse Current 0.05 to 100 uA, Reverse Voltage 50 V, Non-Repetitive Peak Forward Current 2.5 A (surge). Tags: Axial-Lead. More details for JAN1N6643 can be seen below.