Professional Tubing Repair - ACRK-4 contains an assortment of KLEDGE-LOK fittings for permanent leak repair of 5/16in, 3/8in, 1/2in, 5/8in, and 3/4in diameters of cracked, kinked or leaking lines without removing the lines from the vehicle. Designed to be used in conjunction with the professional KLEDGE-LOK tool (SLK-2). Repairs can be made on SAE and metric tube-to-tube, tube-to-rubber hose, or tube block-offs. See why this system was awarded the 2013 Most Innovative New Product by the Mobile Air Conditioning Society.