The Cotterman Series A ladders are set-up aluminum ladders. The primary advantages to aluminum ladders are the light weight and corrosion resistant properties of the material. The climbing angle is 59 degrees, with 7" deep steps and 14" deep top step. All ladders have spring loaded casters that retract when weight is applied. Tread choices are solid ribbed tread for medium duty or office environments or Grip Strut for heavy duty environments. The load rating is 350lbs.