129509 Strip heaters are also known as OT-1850 with 240 volts and 500 watts.  The overall length of these electrical heaters is 17-7/8".  The overall width of these heaters is 1-1/2", and the height with terminals is 15/16".  These strip heaters are 3/8" thick with a heated length of 16.4".  A rust resisting iron sheath encloses the electrical heater.  There are two offset #10-32 terminals on one end of the heater.  These bar heaters have two slots (one on each end) measuring 5/16" by 1/2".  CLICK HERE to view a detailed drawing of these 1.5" wide strip heaters.