This style of bag , has a back overlap seal and a crimp seal across the bottom which is folded over and a length of tape is applied for added strength. 

The tape application also creates a block bottom base to stand up better than a normal Crimp bag.

The Titan Weld Bag is used mainly for Whole foods, Pulses, Pastas, Granulated products, Salts etc and is airtight when sealed. They a lot stronger than a normal Crimp Bottom Bag, Up to 2 kgs can be packed in a 50mu bag without the need to upgrade to a laminate.

Sized as:

Width x Width+Gusset x Length