Part Number 2069: Masimo Rainbow sensor is for use with Masimo monitors that require the Masimo Rainbow sensors to read SpO2, SpCO (carbon monoxide) and SpMet (methemoglobin). The adjustable hinge allows the sensor to be adjusted to various finger sizes. For short term or "spot check" monitoring. Recommended weight range: greater than 30kg. Recommended monitoring site: Ring or middle finger of non-dominant hand. Sensors must be repositioned every 4 hours.