Fisher & Paykel has developed a line of high-performance circuits that has a patented spiral wire circuit technology that is unique to the industry. This technology allows for more consistent temperature delivery throughout the circuit, helping to maintain a virtually condensate-free environment and improvement for optimal humidification. 5Ft Length with Pressure Port and 1/8in pressure line. All single-heated limb circuits can be connected to either a 900MR901 or 900MR900 heated wire adapter for MR730 humidifiers and a 900MR801 or 900MR800 heated wire adapter for MR850 humidifiers.