The SMC AR40K-04 is a high-performance modular style air regulator designed for precise control of pneumatic system pressure. Part of the AR-K series, it features a built-in, square-embedded pressure gauge for easy monitoring and a compact design. The modular construction allows for simple connection to other SMC air preparation equipment, such as filters and lubricators, to create a complete FRL unit. Its improved visibility and easy-to-operate adjustment knob make setting and maintaining the desired pressure straightforward and reliable, ensuring optimal performance and longevity of your pneumatic components.