em-trak B921 Class B AIS Transceiver - 2W CSTDMA – Marine Boat Replacement Part is organized for navigation, gauges & instruments shoppers who need a clear, professional marine parts buying experience.B921 Class B AIS Transceiver - 2W CSTDMA **As the FCC requires all units sold in the US to be programmed by a qualified technician. Please submit the form below for programming at the time of purchase. A copy of the MMSI registration or FCC Ship Station License is required along with the vessel master or owner's signature on the completed programming form.** Click here to download form . The B921 is a 2W CSTDMA Class B AIS transceiver, delivering em-trak's advanced performance and reliability through next-gen technology. Small and durable, this trusted transceiver processes all AIS transmissions in real-time, even at the range limit, so you always have the complete picture and the time to reFitment & Product DetailsBrand / Manufacturer: em-trak Search-optimized by brand, system, part type, and fitment cues. Verify compatibility with your original part number, engine model, and application before ordering. Built for boat owners, e-commerce shoppers, and professional marine service teams.