When evaluating a stair climbing trolley, the most critical factor is the tri-wheel design or caterpillar track system, which allows the unit to traverse steps smoothly. You must verify the maximum load capacity, typically ranging from 150kg to 500kg depending on whether it is manual or electric. For electric models, prioritize brushless motors for longevity and lithium-ion batteries with a capacity of at least 24V/12Ah to ensure sufficient operation time per charge. Additionally, the frame should be constructed from reinforced aluminum alloy or carbon steel to balance weight and structural integrity.