The screen separating the Main Meeting Room and Small Hall consists of a pair of counterbalanced sections constructed of a stout framework of pine with panelling on each side, some twenty-four feet (7.3m) long and five and a half inches (140mm) thick. The lower section, which is rectangular and seven feet (2.14m) high, can be lowered into a pit below the meeting house floor, while the upper section, which is roughly semi-circular and seven foot nine inches (2.36m) high, moves up into the roof space. In the centre of the lower section is a pair of doors, back to back, one opening into the Main Meeting Room and the other into the Small Hall, allowing access from one room to the other while the screen is in place.
A heavy chain each side, attached to the upper and lower sections and running over a pulley, provides the counter-balance mechanism and ensures that the upper section moves up while the lower moves down and vice versa. Two lighter chains, one attached to the top centre of the upper section, and one attached to the bottom of a post fixed below the lower section, wind round a pair of drums in a cupboard in the entrance lobby. These are operated by a windlass and allow one person to raise and lower the screen.
With the screen fully open, the top edge of the lower portion is well below floor level. Eleven hinged wooden blocks below the floor boards can be swung into position across the top of the section and three boards placed on top of them to fill the gap in the floor.
The animation below shows the operation of the screen. The counterbalance chains are omitted for clarity.