Molyslip is a UK company
https://www.molyslip.co.uk/aboutmolyslip/
Liquimoly is a German company
https://www.liqui-moly.com/en/gb/com.../about-us.html
I like the liquimoly products
Never used molyslip stuff but have heard good things - it has been around for yonks
(May be they are owned by the same umbrella capital finance company but they seem to be operating independently)