Yes, the pole crook, those were the days. It wasn't in use very long for me because I was shown how to bead elastic through the No1, a bead from a necklace at the end of the No1 with PTFE tape around the tip, it was wound around the tip just overlapping then poked down the inside of the tip with the end of a stick float.
That was back in 76 I remember.
I suppose it was the start of internal elastics. I have no idea who came up with the idea but it spread like wildfire on the local match circuit soon everyone had a version.