My Bad Hav , It is called Iron out.
Product Overview
Super Iron Out is a superior solution to any rust stain. Cleans rust stains on toilet bowls, toilet tanks, white clothing, sinks, tubs, tile and showers, appliances -washers and dishwashers, water softeners, concrete and exterior walls. Super Iron Out chemically changes rust and iron into a clear, soluble state that easily rinses away without scrubbing. It does not contain harsh or abrasive chemicals and is safe for white clothes, fiberglass, porcelain, and acrylic finishes.
#1 brand rust stain remover in US because it works better on rust stains than any other product
Highly effective powder form allows user most flexibility for most uses
Effective, easy to use and safe on all surfaces
Eliminates iron build-up if water softener is on hard water
Note: product may vary by store