Steel external tube diameter: 40 x 1.2 millimeters
Aluminium internal tube diameter: 35 x 1.2 millimeters
Steel squared base: 35 x 1.2 millimeters
steel external tube diam. 40 x 1.2 millimeters and aluminium internal tube diameter 35 x 1.2 millimeters. Steel squared base 35 x 1.2 millimeters. Innovative design. Automatic push button mechanism that allows the tube lift but avoids the fall.