Yeah, I had never heard of it either.
It comes up on eBay as the below.
Neutrarust 661® - The Original Rust Converter & Primer Treatment 1 Litre
MOD & NATO approved
Free UK Delivery and dispatched within one working day!
The Original Rust Converter developed over 40 years ago and still recognised around the world as the best rust treatment for almost any rusted metal project.
Neutrarust 661® – This incredible British product is hailed by many as the Original and Best Rust Converter. This is the Fast Working rust treatment for professional & domestic uses.
Superior coating consistency providing high quality surface ready for painting. Easy to apply and perfect for automotive applications, ships, ballast tanks, oil rigs, refineries, power stations, boat yards, bridges, pipework, railways, subframes, chassis protection, engine mountings. In fact, anywhere that corroded ferrous materials can be found. Can be used above and below the water line. A mineral acid-free rust treatment, formulated to neutralise corrosion on ferrous materials and components also acts as a primer. It has been designed to react rapidly on ferrous corrosion, leaving a tough insoluble ready-to-paint acrylic coating, without the use of hazardous mineral acids. Once dry, the coating can be overpainted with a paint suitable for your individual application.
Supplied ready for use.
Simple to use & converts rust to READY-TO-PAINT surface
Neutralises the corrosion process
Water based – Classified as non-hazardous
Minimum surface preparation required
Superior smooth "wetting out" surface application
Produces a hard, water insoluble hydrophobic film
Mineral acid free
Compatible with most paint products
COVERAGE: 10 to 12 square metres per litre
Specially tested against salt spray for sea-going vessels and off shore applications
MANUFACTURED IN THE UK
Instructions:
Clean off any oil, grease, loose flakes of rust etc. Rinse with clean water.
Brush, roll or spray on to surface (COVERAGE: 10-12 square metres)
Store in temperatures between 5 °C and 35 °C and use within 12 months of opening
Authentic original Neutrarust® product - managed by Polycote UK