After reading some of the comments on other issues I believe it is the blades.
Wahay!
I'm a n00b at window cleaning, relatively speaking; and I answered a question correctly!
PS.
Does anyone want to buy £65.00 worth of defective Unger Soft rubber for £20 plus postage and packing?
We use Unger Soft all the time. How is it defective?
Bear,
E-mail me your address and I'll send you £40 to £50 worth of Unger Soft Rubber.
Free.
I bought them from Screwfix.
I tried different handles and different channels and they all worked out really bad. They're each 42" long, coiled and still in their Unger wrapper.
But they are really bad. At first I thought I had a bad batch. Then I thought I had a bent channel. Then I thought I had a dodgy channel holder.
In the end I realised the rubbers were really naff. I should really send them back with a complaint.
As a final test, I'll try another one out tomorrow and use it.
In the mean time, e-mail me your address.
If they're still naff, I'll send you the lot!