I have put up some new stock of US made chokes (and Hammond made in Taiwan chokes). The sad news is that Hammond bought these from Bourne and that the manufacturer stopped making them in 2016. Despite trying to find replacements, Hammond has been unable to do so. I have made a limited selection of my current stock 3 and 4 pi chokes available. I have other RF chokes of 2.4 x 300ma size (for example - and others) but they are not 3-pi.
If you NEED them, RF Parts in the US sell some and so do Surplus Sales of Nebraska. Ebay has 4pi 2.5mH 160ma chokes for about $12 AUS each (60c in the US dollar) posted (you have to buy 4).
If you are in desperate need, email me. I may have some which I have not put up on the site.....