The 2SJ166-T1B-A is a P-channel MOSFET, a switching or linear-control device for load-side high-side switching where a positive supply rail is connected to the source and the load is pulled to ground through the drain. Fully ROHS3 compliant, so it qualifies for BOMs that require the latest EU restriction directive without exemption.
For higher-volume pick-and-place, confirm whether your assembler can handle Bulk tubes or if a reeled variant of the same die is preferred.