Battery charge devices; Converters, electric

Metal casing centralizers for oil well pipes; wellbore centralizers for pipe strings, namely, split, clamp-on, one-piece and solid cast types, all made of metal; fabricated and cast metal downhole equipment, namely, stop collars and stabbing boards; prefabricated metal platforms; prefabricated work platforms of metal, including work platforms for use in drilling operations; metal drill collars; metal stop collars for pipes

Battery charge devices; Converters