Sierra 18-5898 Temperature Sender - 1/2"-14 NPT The Sierra 18-5898 Temperature Sender features a 1/2"-14 NPT thread, 10-32 stud terminal type and 240 DS range. Each Sierra product meets or exceeds the original equipment part it replaces. Sierra Temperature Sender Range: 240 DS Sierra part number: 18-5898 Thread Size: 1/2" or 12.7mm -14 NPT Terminal Type: 10-32 stud