Solvit's PupSTEP Wood Stairs offer a beautiful and convenient alternative for helping pets reach their favorite places. The sturdy construction and rich walnut finish means these stairs can be proudly displayed in any home. If needed, these stairs can be folded flat for convenient storage or transport. Safety side rails are built into the design so your pet can climb up and down with confidence. No assembly required. Available in two sizes: the Large model is intended for small- to medium-sized pets, due to the size of the individual step sections. For larger pets, or for any pet needing to access a very tall bed, choose the Extra Large model. Overall dimensions of the Large model is 24 long x 16 wide x 20 high; the treads are each 6 inches deep, 15 inches wide, and 4.75 inches apart. The Extra Large model measures 30 long x 19 wide x 25 high; the treads are each 7.5 inches deep, 18 inches wide, and 6 inches apart.