🔧6 Ball bearings. Made of solid Steel, great for corrosion resistance and has a longer lifetime. 🔧A better grip when connecting and disconnecting; sleeve guard helps reduce the risk of accidental disconnects and protects the coupler sleeve. 🔧1/4 Inch Female Threads Size: This coupler is used to connect components to an air compressor stuff. Please confirm the threads size before buying. 🔧1/4 inch NPT female thread × 3/8 inch body size, interchangeable with most manufacturers; maximum working pressure is 300 psi. 🔧These steel air quick connector couplers are all well organized in a strong polybag case, easy for storage and carrying out for work, 9pcs/bag. Two Year limited quality. Air Tool Fittings