The TT-555 is a direct output temperature Sensor used to measure air temperature, especially in fan-coil units etc, and contain either a high quality thermistor, nickel or platinum sensing element. The standard cable length is two metres of 2-core screened cable. Longer lengths can be made to order. ——— Low Smoke Zero Halogen cable is available for these products for an additional cost of 3.30/$5/4 per metre. To order this product, please add the suffix -LSZH to your product code when ordering or speak with our Internal Sales Team.