Newer designs, such as those manufactured by medical instrument maker Charriere featured interchangeable claws. He liked to call the building a "medical instrument". Aalto liked to call the building a "medical instrument". Gag designs, like other medical instrument designs, are often named after their inventors. The USM "Auriga" was originally designed by artist Nigel Phelps and resembled a medical instrument. He donated his medical instrument collections, books, trade cards and ephemera to the Kislak Center. A reflex hammer is a medical instrument used by practitioners to test deep tendon reflexes. The [[orchidometer]] is a medical instrument to measure the volume of the testicles.