Machined stainless steel chest piece Double sided chest piece technology Diaphragm Diameter 4.5 cm (1.75 Inch approx) & Bell Diameter 3.2 cm (1.25 Inch approx) Spare diaphragm & soft ear tips provided absolutely free of cost Reliable & High Acoustic Sensitivity offer an advantage to Health Care Professionals when listening to Heart, Lung and Blood Pressure Sounds