Steamist SM Series steam unit main circuit board original P/N 007-5169 also known as a LLC1300-3 circuit board. The newer Steamist OEM replacement circuit board is also known as a LLC1700-4 circuit board or part number 007-5380 4K. Carefully removed from a very lightly used and working SM steam unit that was upgraded to the newer TSG Series. Professionally cleaned and fully tested, and functioning perfectly. This circuit board can also be use in place of the part number 007-5182. Also known as a LLC1300-2 with the part number of 007-5182. The LLC1300-3 circuit board is for SM Steamist units with auto drains systems, and can be used in systems without auto drains, while the LLC1300-2 can be used in SM systems without auto drains only. Please be sure this part will work for your application as there is a no return policy. Email with any questions before purchasing.