Buyers must prioritize material quality, specifically low-carbon steel or stainless steel, to ensure corrosion resistance. The wall thickness of the tubes should be at least 1.2mm to 1.5mm to withstand high pressure. Additionally, verify the Heat Output (BTU/Wattage) calculations to ensure they meet the specific square footage requirements of the installation site. For finish durability, look for electrolytic powder coating which prevents peeling and rusting in high-humidity environments like bathrooms.