Rubber/aluminium strip in front floor area - used in 1934 cars. An underlay material was laid with the edges retained in the rubber section, to provide draught control.
Riley body details -
Rubber/aluminium section in front floor area - drawing of section
Hobson Telegauge Tank Unit - general arrangement drawing
The tank unit shown has two 'air cups'. I have also seen tank units with three.
Riley '9' March Special Screen Storage box - General arrangement drawing.