MRCOOL DIY50-1438C-O 50 Ft Pre-Charged Line Set is a refrigerant connection assembly designed for compatible MRCOOL DIY ductless mini-split air conditioners and heat pump systems. It works by providing a sealed, pre-charged pathway for refrigerant to circulate efficiently between the indoor and outdoor units, eliminating the need for field refrigerant charging during installation. https://www.partshnc.com/mrcool-diy50-1438c-o-50ft-pre-charged-mini-split-line-set