STI 42687-0440 MS4344BX Light Curtain Transmitter

The STI MiniSafe MS4344BX light curtain transmitter (42687-0440) is a rugged safety device designed to guard hazardous machine access in industrial environments. It is the transmitter counterpart in STI’s MiniSafe MS4300 family and is commonly paired with the MS4344BR receiver to form a two‑piece optical safety curtain. This unit is frequently sold as a used or refurbished item, with typical listings noting a weight around 4 lb and a NEMA 4 enclosure, making it suitable for demanding shop-floor conditions. The MS4344BX is specified for a 44‑inch protective height and a sensing range reported by listings as 1 to 30 feet, enabling coverage of taller and longer access points. The part number 42687-0440 uniquely identifies this transmitter and it is intended to operate in concert with its corresponding receiver to create a beam-based guarding system that halts equipment when a beam is interrupted. While delivered as a standalone transmitter in many listings, its practical use is as part of a complete mini‑safe light curtain setup for machine guarding, suitable for integration into PLC‑controlled safety circuits where a reliable, hands‑free protective barrier is required.