The Upton 251 microphone is a condenser microphone based on the classic Telefunken Ela M 251 which was produced by AKG from around 1960 to 1965. The original 251 is widely regarded to be one of the finest microphones ever made and is great for many recording applications. Upton's 251 utilizes their CK12 capsule, their T14 transformer as well as the original circuit design.