Starrett 3805B Electronic Shore A Durometer, designed to measure the hardness of soft materials such as rubber and plastics.It features a large LCD screen for displaying measurements and a simple three-button interface for hold, power, and zeroing functions.The device is designed to be handheld and is used to test materials like soft vulcanized rubber, natural nitrile, and various elastomers.It operates by applying a spring-loaded indenter to the material to determine its resistance level on the Shore A scale.