What this 8-position header does for your board
The 644752-8: It mates with the corresponding MTA-156 receptacle housing to make a board-to-wire connection. The 3.96mm pitch is wider than the common 0.100" headers, so the board footprint and the mating receptacle must match this spacing exactly — a 0.100" receptacle won't fit.
In practice, the 3.96mm pitch and tin-plated contacts typically support 5-7A per circuit with 18-20 AWG wire. Voltage rating is 600VAC, which covers line-voltage control circuits and machinery power distribution.
Housing and flammability rating
The insulator is natural-colored, glass-filled thermoplastic rated UL94 V-0. The header is shrouded on one wall, which provides some keying and prevents the mating plug from being inserted backwards.