MDF Instruments have been handcrafted with pride since 1971. Signature MDF quality is backed by a lifetime warranty that protects against defects in materials and craftsmanship. Also offered with the purchase of an MDF Stethoscope is the MDF Free Parts for Life Program that offers free replacement parts for the life of the instrument. Replacement parts include silicone non-chill and retaining rings, diaphragm, ID Tag and ComfortSeal ear tips.