Roll End Tuck Front refers to the model that defines the enclosure method of the box and "mailer box" is how the box is used. They look the same when they are assembled, however, the paper thickness will determine its use. You can use a lighter white-bleached cardstock such as 18pt to 24pt for lighter-weight products that are packaged within the RETF box. If you choose an 18pt to 24pt paper stock you will not be able to use it as the shipping box but rather the box that the product itself is packaged in. When you order a RETF box you can choose a range of paperboard material whereas if you are ordering specifically a mailer box you will most likely use it as a protective box to ship as a parcel. For that reason, a Mailer Box should only be made with a corrugated sheet, such as a 32 B Flute.