The MRCOOL NV15-3834-O Central Ducted 15 Ft 3/8 x 3/4 R-454B No-Vac Pre-Charged Line Set is a refrigerant connection kit designed for compatible MRCOOL central ducted HVAC systems. It connects the indoor air handler to the outdoor condenser, allowing R-454B refrigerant to circulate between the components for efficient heating and cooling. Featuring 3/8-inch liquid and 3/4-inch suction... https://www.partshnc.com/mrcool-no-vac-pre-charged-line-set-3-8-x-3-4-model-nv15-3834-o