Based on the product dimensions you provided (Length: 103 cm, Width: 73 cm, Height: 71.5 cm), this corresponds approximately to the MIMsafe Variocage Double XL size. The XL model has dimensions close to 81 cm width (38.9 in) and 71.5 cm height (28.1 in), which matches your height and width most closely compared to the Large size, which is narrower and shorter. The length of 103 cm (about 40.5 in) also fits the telescoping length range of the XL model (31.8« to 40.5»).

Therefore, the size is most likely the XL (X Large) model.