MDF likes to describe themselves as a boutique manufacturer of stethoscopes. When you look at their website and ads they do give off that vibe of being a chique design company. MDF Instruments has existed since 1971, and has continued to base their company in the United States, despite doing extensive international business. MDF like many medical equipment companies does have product offerings outside of their line of stethoscopes, but they remain best known for their stethoscopes. MDF is very customer-centric in the way their approach business. If you visit their website you will notice that in addition to their lifetime warranty offering, they also offer free-parts-for-life for their stethoscopes.