This product has been unfairly given a 1 star review because another reviwer failed to read the bottle.
Nikwax Tech Wash is not a reproofer. It is a safe cleaner for cleaning waterproof items. It is safe because it will PRESERVE any existing waterproofing treatment (that which causes water to bead) and will also clean any waterproof membrane such as eVent or Gore-Tex returning to their original breathability, as ordinary detergents will destroy the treatment.
If you have a jacket that has had it's DWR (Durable Water Repellency) diminished then you MUST used a secondary product after first washing with Tech Wash to restore that water repellency, of which Nikwax and Granger's produce several.
It is wholly unfair and innacurate to rate this product 1 star.