\$\begingroup\$ Judging by the reference designator, it is probably a transient suppressor diode. That's all I can make of it. \$\endgroup\$– BartJan 22, 2020 at 14:42
It looks like the 160V transient suppressor diode [1SMB170AT3] from On Semi (https://nl.mouser.com/datasheet/2/308/1SMB5.0AT3-D-108677.pdf)
but it doesn't clarify the K shown in on the diode on the picture.