Which function has a Rod Dipper

[Geri]

Hello Everybody

In the catalog from my parts Trader i found a part called Rot Dipper.

On my 1955 Inline 6 i never seen this part....... well according to the catalog of the Trader the part is only used in motors from 1933 until 1953.

Whats the function of this Rod Dipper? Is it a special or bonus part? Is it possible/necessary or helpfull to upgrade the 1955er Inline 6

I hope the bad picture may help you.

Thanks a lot

Geri