12-position single-row footprint
The 66951-012LF: The single row keeps the board width narrow; the 0.142" (3.60mm) solder tail length gives a solid through-hole joint on standard 1.6mm PCBs.
1250V rating and wide thermal range
Voltage rating is 1250V — unusually high for a 2.54mm pitch signal connector; this suits it for power distribution or high-voltage signal paths inside equipment. Housing is glass-filled polyester, UL94 V-0 rated — required for equipment inside a UL-listed enclosure.
