The 3.96 mm pitch is wide enough to route a single power or signal wire per position without crowding the board — the 0.156" centres match standard crimp housings and give enough creepage for the 250 V rating without forcing an oversized footprint.
The B2P-VH uses a 1-wall shroud — the pins are exposed on three sides, which makes it easier to visually align the mate but offers less pin protection during handling. The B2P-VH-FB-B shares the same 2-position, 3.96 mm pitch, 10 A, 250 V electricals but wraps the pins in a 4-wall shroud with a board guide. If your assembly sees rough handling or needs positive alignment before the pins engage, the 4-wall version is the better pick; if you're replacing a header on an existing board and the housing already fits the 1-wall profile, the B2P-VH drops straight in.