It is a flexible bag as it comes with detachable shoulder straps and messenger straps. (babieslounge.com)
Each bag has a removable bottle holder, change pad, diaper and wipes carrier, and detachable shoulder strap giving mommy lots of functionality. (thefashionablehousewife.com)
This set can be worn as a double baby carrier or as a single baby carrier depending on your needs thanks to the extra detachable shoulder straps. (babycarrierreviewguide.com)