Hi Jouk
Sorry ive not replied but been out for a couple of hours.
Bottom section of pole is 30mm dia.
I bought a 6mtr pole and removed the top 2 sections. when i add the goose neck it gives me a 4.6mtr pole which is more than enough reach for domestic work.
If you look on the site they do a 7mtr carbon fiber one that is not telescopic, it,s sectional each piece goes over the previous one like a fishing pole, with these you can make
the pole as long or short as you require.If you want to see the fishing pole with goose neck look at page 13 about half way down ( DIY POLE FOR £12.50 )
here some pics