Originally Posted by Roy Mander
Hi Fellas, I got one of those as well at the back of the battery. Its is for clipping over the positive post of the battery to prevent accidental shorting.
No it is not, it fits in the front top end of the battery to collect acid spillage from the vent hole.
On our car the rear end vent is plugged with a small plastic plug and the item in question goes in the front plug hole to collect acid spillage and let the gases exhaust.
Not having the plug and vent in place allows any acid that spills get on your car and eat at the metal.
This feature may not be on all batteries, on my replacement battery which has the two vent holes I used both of the plugs from the OEM battery and the red terminal cover.