Glass Hydrometer range 1100-1300 with coloured zones, blue, white and red for charged, partly charged, uncharged conditions respectively. Glass body, compressible rubber bulb and rubber tube with fitting to body in card box.

In above a Jolly Air Thermometer bulb 50mm dia is mounted on a wooden frame which can be fixed at three places, up, middle and down on the stand and enable the apparatus to be used as Jolly's Apparatus.