The AT40 from AXRTEC is a professional 2-stage aluminum tripod featuring a 75mm bowl base. It's an enhanced version of AT30.It supports up to 88.2lbs, and both leg stages with twin tube design that ensures more stable operation.With a mid-level spreader attached and ergonomic twist leg lock knob at each stage of each leg,the tripod offers a height range of 28.1" to 69.3". Also,there is a hook on one of the legs for easy storage.