I bought this microwave to replace an existing under counter Bosch.  I had to choose the mod er l to fit the existing space in recently installed custom cabinets.   The previous microwave was a 500 series but the new 500 was just slightly too big.  The 300 fit perfectly but has fewer features.  It does perform very well and the new lighting is very good and the vent fan is great.  I am happy with the model but wish all models for  under cabinet were standard sizes.  That is the only complaint but I am glad I could at least replace with a Bosch.  I am very impressed with the quality of all their appliances.