When evaluating aluminium step ladders, prioritize the Alloy Grade, typically 6063-T5 or 6061-T6, which offers the best balance of weight and structural strength. Ensure the Load Capacity meets your target market needs, such as Type IA (300 lbs/136 kg) for heavy-duty industrial use or Type II (225 lbs/102 kg) for commercial tasks. Additionally, check the Step Depth (minimum 80mm recommended for comfort) and the presence of Anti-slip Ribbing on the treads and Non-marring Rubber Feet for stability.