Oooh - didn't know Avenger Tiger ones were the same. They are the later aluminium ones - I used to have a pair of those. One of them unscrewed itself and fell off. I bought them to replace the earlier brass ones I had on my 1840 after they both fell off. They do that.
Here is an item of possible interest to owners of holbay engined cars, listed for the avenger tiger but these are the correct airbox fixings often lost or damaged over time;