The K65 tube system has been developed in response to the use of R744 as an environmentally friendly refrigerant e.g. for supermarket refrigeration systems. K65 simplifies the selection process, as the Wieland K65 alloy provides an enhanced mechanical strength high enough to withstand the huge pressure ratings required. K65 has excellent processing properties that are similar to those of copper. Wieland K65 tubes can easily be brazed to Conex Baenninger K65 fittings. This K65 system is covered by a joint system guarantee that includes CO2 applications. Having such a high mechanical strength, the K65 tube can be made with comparatively thin walls allowing for an economical utilization of material, while still meeting high technical demands. The thinner walls of the tubes not only saves on material, but results in a lighter weight product that is easier to handle, for example, when mounting the pipes on ceilings.