Radiometer with four lightweight metal arms.

• Includes black and white vanes in color
• Mounted on round plastic molded base
• Glass bulb with 70 mm dia.

Comprising partly evacuated glass bulb approx. 70 mm diameter, containing at its center a fine pivot which supports four light weight metal arms. One side of each vane is blackened, the reverse side is bright. Mounted on round plastic molded base.