An azeotropic blend of R-125 and R-143a intended for low and medium temperature refrigeration systems. Similar to R-404A in operation, most new equipment has been rated to use either blend. There will be slightly higher pressures and capacity with R-507 compared to R-404A. R-507 requires polyolester (POE) lubricant, which is usually charged into new equipment. If retrofitting existing equipment, the original oil must be replaced with POE.