MRCOOL DIY25-1412C-O 25 Ft R-454B Pre-Charged Line set with Pro Cable is a connection line set designed for compatible MRCOOL DIY ductless mini-split air conditioning and heat pump systems. It works by providing a sealed, pre-charged pathway for R-454B refrigerant between the indoor and outdoor units, while the integrated Pro Cable supports electrical communication and power. https://www.partshnc.com/mrcoolr-diy-line-set-diy25-1412c-o