Nidus Corona Knob Passage Set CDFWHSC Nidus door hardware is innovative and provides a modern look to any home. They offer a great selection of levers, locks and door accessories. As experienced locksmiths we have purchased their door furniture for many years, having confidence both in the company and its products. The Corona range of powdercoated knobs has the same shape, appearance, and feel of porcelain knobs, but is made from a metal diecast material, giving greater product strength and durability than porcelain. This product also uses the same backplate and fixing design as Nidus porcelain and Wentworth products. Suits a standard 50mm hole (and up to 54mm hole).