This ARS Cryo 4K is a customized closed-cycle cryocooler capable of a performing electrical, optical and optoe-lectronic measurements from 350 K down to 10 K. For optical measurements, the system employs a helium gas exchange between the cryocooler and the sample stage to reduce vibrations and has two high-purity quartz win-dows for optical access. Currently, the system is setup for electrical transport measurements and is capable of accepting devices with up to 32 electrical contacts.