Features: Engineered with duals fluorosilicone o rings and ptfe noise dampening washers, this stainless steel check valves ensures leak proof performances and <35db operation in aquarium co2 systems and air hoses. Features 304 stainless steel spring mechanism, providing corrosion resistance and space saving installation flexibility. Ideal for aquarium enthusiasts, home beverage appliance owners using sodas makers, and commercial drink stations requiring co2 gas control. Prevents liquid backflow in pressurized environments like beer fermenters, water machines, and coffee shop carbonation systems. Outperforming single seal valves in durability for marine equipment and food grade applications. Specifications: Materials: Stainless Steel Size: Length Approx.3.6cm/1.41inch Weight:50g Quantity:2pcs Package Includes: 2pcs Stainless Steel Check valves note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item.