Tex 45 is recommeded for Domestic machines
Tex 70 is recommended for Industrial Machines
Both are Bonded Polyester, some domestic machines may be picky when it comes to thread, if that is your machine we recommend against getting the Tex 45. That being said the Tex 45 is a great strong thread for domestic machines because it is bonded. Its a great alternative to Guterman as it is in fact stronger. That being said we are waiting for regular non bonded polyester thread to come that will be similar to the brand guterman, so those with picky machines, dont worry too much because we have you in mind as well! The Tex70 sews smoothly; you will definitely want to grab some for your thread collection!