hi, anyone tell me if Littmann master classic II stethoscope is a good one?I got it as a gift,its the one with single sided chest piece- press harder and its a diaphragm, press lightly and it works as a bell. It sounds ok but I like steths with two sided chest pieces. Anyone tell me if this works well, then I can keep it, o/w I want to sell it off to anyone interested, so I can buy the kind I want. any suggestions for a two sided steth?