Ladder, A Frame 5 Step Ladder Extension, 17 Ft Anti-Slip Multi Position Ladder, Storage Folding Ladder, 330 lbs Security Load Telescoping Aluminum Ladders for Stairs Home Indoor Outdoor RoofSTRONGER: using high quality sturdy aluminum alloy, aluminum tube thickness reinforced, robot welding craft, high precision and consistence, the wider and longer undulating lines on the rungs, reduce fatigue and foot pain, and avoid slippage of the sole during use as much as possible, when completely unfolding this lightweight ladder, the careful design of the u shaped lock and auto limit spring lock offer double safe reinforcements, reduce our stress