$33 3 IN 1 STAIR CLIMBER CONVERTIBLE HAND TRUCK BOX CARDBOARD CRATE 3D model by SURF3D. Available on CGTrader with 1111493 polys and 839909 vertices. Check it out on CGHub.
STL (Stereolithography, filesize: 53 MB), OBJ (OBJ, filesize: 110 MB), 3DS (3D Studio, filesize: 31 MB), 3DM (Rhinoceros 3D, filesize: 29.8 MB), BLEND (Blender, filesize: 96.2 MB), MAX (Autodesk 3ds Max, filesize: 193 MB), DAE (Collada, filesize: 174 MB), GLTF (glTF, filesize: 32.4 MB), FBX (Autodesk FBX, filesize: 32.5 MB), STP (STEP, filesize: 10.9 MB), DWG (AutoCAD, filesize: 17.6 MB), SKP (Sketchup, filesize: 15.1 MB), IGE (IGES, filesize: 21.7 MB), SAT (3D ACIS, filesize: 64.3 MB)