The Instantor RP519540 ACR R-Press 3/4" x 5/8" Reducing Coupler is a high-performance copper R-Press fitting designed to connect two different sizes of ACR copper tube in refrigeration, air conditioning, heat pump, VRF and VRV pipework. Part of the Instantor R-Press system, it provides a fast, reliable and flame-free way to reduce pipe size without the need for brazing. Featuring a 3/4" press connection at one end and a 5/8" press connection at the other, this reducing coupler allows installers to make a neat transition between tube diameters while maintaining a secure mechanical joint. Its refrigerant-grade copper construction and HNBR sealing element are engineered for high-pressure ACR applications when installed using compatible V-profile press tools and jaws in accordance with manufacturer instructions. Supplied in packs of 2, the RP519540 offers a convenient, professional solution for joining different copper tube sizes on new installations or refurbishment projects.