Waterworks | Opus Volume Control Valve Trim with Crystal Egg Handle in Chrome Opus incorporates a range of sophisticated aesthetic notes, with graceful curves that create a jewel-like refinement. FEATURES: Brass material is used for trim and valve component parts. The manufacturing process encompasses casting, turning, stamping, hand-fitting and hand polishing. Two distinctly different materials, metal and crystal, have been combined to create an elegant fitting. Eased curves and reflective forms carry the message of cleanliness and clarity.