What is the red dot on the item shown in the picture?
B JANE G I believe that it is a burst valve in the event of over filling but I am not sure. Sorry.
DANIE T A red dot visable on the gauge ia an attchment to the pressure indicating needle. It only appears when the pressure is very low
EGLADIR X There is no red dot on mine. If you mean on the gauge face then there is a green zone and a red zone to show high and low pressure in the pony tank.
KURT W THE RED ITEM IS THE ARROW THAT INDICATES PRESSURE
Marilyn S That is an overpressure safety plug. In case of any failure, the excess pressure will be vented through that plug preventing the whole gauge from exploding.