Bilt Hamber surfex-HD is a highly concentrated multi-purpose cleaner, and is an unbeatable choice for tackling neglected wheel arches, engine bays and undercarriage areas. It also excels at stripping previously applied sealants and waxes, and at general exterior cleaning duties when used at higher dilution rates. However, its concentrated nature must not be taken lightly, and care should always be taken to use an appropriate dilution strength for the task in hand, and to avoid letting it dry out fully before it's rinsed off, otherwise permanent stains may occur. In short, as long as it's used with care and at the recommended dilution ratios, Bilt Hamber surfex-HD is a brilliant value for money intensive cleaning product, and one that we happily recommend to home enthusiasts and professional detailers alike. Since testing it, it's quickly become our go to product for all intensive cleaning tasks!