2.50 mm Pitch SMT Header, 4 Positions — JST LEX Series
The EM04B-LEXSS-TF(HF): It uses a 0.098" (2.50 mm) pitch, which sets the board footprint spacing and determines the mating receptacle it pairs with. Tin-plated contacts on a copper alloy base carry a 3 A rating when terminated with 22 AWG wire — the current is wire-gauge dependent, so expect derating with smaller conductors. The 300 V voltage rating gives adequate headroom for typical signal-level and low-power distribution inside equipment enclosures. That temperature span covers most commercial and industrial cabinet environments without issue.
The solder retention features are molded into the housing; they increase the hold force on the pads after reflow, which matters if the cable assembly sees vibration or repeated mating cycles. The base product number EM04B-LE tells you this is the 4-position version of the LEX SMT header family. The -TF(HF) suffix indicates tape-and-reel packaging (suitable for pick-and-place) and halogen-free compliance per JST's designation.