COWELL(NINGBO) HARDWARE CO.,LTD is the OEM supplier in Special Ball Bearings, Door and Window Rollers/hardware, smart Motorized Curtain Accessories, Cold forging shafts per customers' drawings and samples. We could develop the products constructed from different materials, structures, shapes, colors etc. 1/. The plastic injected rollers for windows and doors are under the Neutral Salt Spray Testing 240h to 480h, with DIN13126-15 life testing requirement. Our rollers are in stable quality with Smooth rotation, long life operation, small movement, advanced injection technology engineering etc. 2/. The Adjustable Rollers with smooth and long lasting operation, higher performing features like wider adjustment ranges, long rolling life performance, easy installment. It's available in multiple housing choices with any wheels to fit different aluminum. Our rollers ensure alignment across the full adjustment ranges within built-in retention system. 3/. The customized hardware, like plastic parts, stamping parts, cold forging steel parts are widely applied in the window and doors, furniture, householders, transmission system, Industrial drive system etc. We are constantly improving and striving for excellence. We hold a very high regard for our customers, the quality of our products, and our level of customer service.