Permatex 56521 High Performance Thread Sealant, 50 ml, White

Customers find the thread sealant works well, particularly on fuel fittings and head studs, and is better than Teflon/PTFE tape. The product effectively seals fuel, oil, and water connections and is easy to use, with one customer noting it's easier to work with than tape sealant. They appreciate its quality and value for money, and one customer mentions it's particularly suitable for air fittings. The durability receives mixed feedback, with some customers reporting it never cured properly.