An expandable bag gives you somewhere to put the extra layer you bought—or stopped wearing—during a trip. This tomtoc starts at a stated 23 liters and opens out to 28 liters, a five-liter increase.
Give the expansion a job
Use the smaller setting for the kit that travels with you every day: a light clothing layer, essentials and whatever work equipment fits the actual compartments. Reserve the added volume for a specific need, such as a change of clothes on an overnight visit. That keeps expansion useful instead of turning it into a permanent invitation to overpack.
The increase is roughly 22 percent of the stated starting capacity. It can help with bulky, compressible items, but the overall liter count does not describe the size of the opening or the proportions of individual compartments. A rigid lunch container and a folded jacket can occupy the same nominal volume very differently.
One name, two packed sizes
The product is marketed for underseat use and mentions Ryanair and Southwest. Treat those airline names as a reason to compare measurements, not as approval for every fare or aircraft. The important measurement is the backpack as you intend to carry it, including a full front pocket and the expanded section.
For a trip with several carriers, plan around the strictest applicable allowance. If your everyday load already requires all 28 liters, a fixed-capacity bag with clearly documented dimensions may be simpler. If you regularly switch between a small commuter load and a modest overnight kit, this tomtoc’s adjustment range is its strongest reason to enter your shortlist.
