I had a couple of 4ft back in the late 80s/early 90s. One had a defect. Flexifoil replaced it with out any question what so ever, immediately. Their quality is absolutely superior.
I also had several 6 ft which I stacked and really enjoyed the most.
I no longer have any of the 4ft or 6ft, but I do have a 10ft, which I have never flown. It was given to me, practically new.
GREAT KITES!