Ah yes Jik telescopic but tapered 4ftish sections so they pull out from inside until they jamm then you give a very slight twist to lock. The mechanical friction lock can work itself loose but in practice its not much of a prob. It happens more when trying to work horizontally as you push against the glass to scrub it can self collapse one section of the pole. Thats why I have another simple locking mechanism but have yet to write it up. in use I have not needed it yet but its there for anyone who is heavy handed or wants to use a heavier brush. Its best with a very light brush say 8oz and the microbore Algarde which is also light.
I am having a lot of fun with it but once its properly sorted will revert to the modular Reload because of the lack of weight.