... .: HT-D111A Characteristics:1. Slim inner monitor unit (Thickness 16.8mm), Outer part diameter: 26mm/32mm2. Outer Part material: Compelete Brass3. Super Clear ... Source: 4 AAA Batteries 7. Color optional: Inner Part: Silver, Golden, Champagne, or custermize Outer Part: Polished Brass,Polished/Satin Chorome, Antique Bronze ...