Electro Signal Lab /  GE Security 250-CO-PLT Adaptor Plate for 250-CO replacing 240-COe [Pack of 5] Pack of 5 250-CO Adapter Plates. Adaptor plates for use when replacing the GE/ESL 240-COe CO detector with the replacement 250-CO SafeAir Carbon Monoxide Detector. Accurate, reliable, quick response Uses commercial-grade detection technology Accurately tracks CO levels over time