Product categories
- AIR MACHINE ACCESSORIES, FITTINGS AND VAC REPLACEMENT PARTS
- HYDRAULIC HOSE FERRULES - FERRULES MANUFACTURER
- INDUSTRIAL AND AUTOMITIVE COUPLERS & CONNECTORS
- PNEUMATIC BLOW GUN KITS AND BLOW GUN PRODUCTS
- PNEUMATIC HOSES
- PNEUMATIC, AUTOMOTIVE HOSE CRIMPERS AND DIES
- TIRE INFLATOR CHUCKS AND AIR FITTINGS
- TIRE INFLATOR GAUGE PRODUCTS
- Uncategorized
- VALVES PARTS PRODUCTS
- WATER BIBBS AND UTILITY WATER NOZZLES
Top rated products

Original Diamond-U 1/4” Series
Offering 1/4" Female Air Hose Fittings & 1/4" M Style Air Hose Fittings!
Over the last century, Diamond-U has been a leading manufacturer of quality ¼” series couplers and connectors. If you’re looking for best in class couplers and connectors for any pneumatic applications, standard or custom, we have the capacity and experience required. We have ample supply of air accessories to cover your need. Don’t hesitate to shop with us whether you want to purchase thousands of couplers and connectors or just a single unit.
Why Choose the Original Diamond-U 1/4” Series Couplers & Connectors?
Since 1923, we have produced quality and affordable products for the automotive and pneumatic industries. We are committed to ensuring that our products meet the industry’s quality standards. You can also count on us to manufacture and assemble customized pneumatic solutions to fit the job at hand. We have an experienced customer support team that can suggest the right products to meet your needs.
Our original Diamond-U ¼” series of steel couplers and connectors are plated to last generations. Come visit our facility. Some of the couplers used in our pneumatic manufacturing systems are original from the 1960’s. We love the moto, “If it’s not broken, don’t fix it!”
These accessories are heat-treated to alleviate wear on the two connecting surfaces. The couplers and connectors have a maximum inlet pressure of 300 PSI, a maximum temperature of 250F, and a molar airflow of 40 standard cubic feet per minute.
At Diamond-U Products, Inc., our ¼” coupler and connector offerings will may give you more options than you need to meet your company’s given application. We offer countless combinations of 1/4" Female Air Hose Fittings and 1/4" M Style Air Hose Fittings to suit your needs. Some of the connectors and coupler types on our original Diamond-U ¼” series include:
- ¼” Female Connector
- ¼” Female Coupler
- ¼” Male Connector
- ¼” Male Coupler
These couplers are designed to resist corrosion, making them ideal for all automotive and pneumatic industrial applications. Not to mention being a solution to most home garage or hobby shop applications.
Ready to Get Started? Purchase Our Diamond-U ¼” Series Couplers and Connectors Today!
Need a custom assembly with one of our quality connectors or couplers, we’ve got you covered at Diamond-U Products! Our 1/4" Female Air Hose Fittings & 1/4" M Style Air Hose Fittings can be configured however you need them right off the factory floor.
Check out our product line to purchase our coupler and connector products today. You can also contact us to order customized products or get your wholesale quote.