Name: Aquarium CO2 Regulator Adapter Connector G5/8 W21.8 Model: SKU978982 Specifications: Color: Silver Material: Stainless Steel Interface: G5/8, W21.8 Features: Brand New & High Quality. Compact & sturdy construction. Single gauge pressure indicator. Compatible with various size of CO2 Cylinders. No wrench needed, handy installation. Convenient and simple. Usage Introduction: 1. Make sure that the is stationary and locked tightly. 2. Please do not add any lubricant. 3. Please do not disassemble the device. 4. With the check counter bubble gauge, the reading is accurate, the built-in check reverse backflow can prevent the backflow phenomenon when the pressure decreases. Adjustment Method: - Close CO2 gauge, install pressure reducing valve, connect equipment. - Open the relief valve trim switch, and adjust the gas output. Smaller than required. - Adjusting pressure reducing valve 8 hours later. Package Included: 1 Pcs CO2 Pressure Gauge Notice: Please allow 1-3cm error due to manual measurement and make sure you do not mind before ordering. Please understand that colors may exist chromatic aberration as the different placement of pictures.