The Omron F39-JG20A-L is a 20-meter single-ended cable assembly for the transmitter side of F3SG-R series safety light curtains, packed in a box and belonging to the F3SG-RA accessory series.
Rated for 20 meters, this cable gives you the reach to separate the transmitter from the controller by that distance — enough for a long conveyor or a wide machine cell without splicing intermediate extension cables. Single-ended means one factory-terminated connector on the cable; the other end is unterminated, so you pull it through conduit or cable tray and land it on your terminal block or I/O module as needed.