The ability to expand and contract makes an expandable backpack a very versatile bag to have for day to day, as well as quick trips.
The Nayo EXP Backpack has a all (50cm) boxy/squarish frame, which can be compressed down to 25 litres and expanded to 40 liters, which is useful for situations that may require you to take a few more things than usual like for a weekend trip.
The Nayo EXP Backpack has three main zippers sewn around the frame of the bag. Two of those zippers provide access to main compartments, while the third zipper (sandwiched in between) is designed to allow the Nayo EXP Backpack to expand in width.
The expandable metal zipper runs all the way around the perimeter of the bag, providing full expansion of all corners of the bag.
Without anything bulky inside the bag, the width of the bag can be kept at just 3 inches, although for most uses the bag's width will be realistically 6 inches. When fully expanded, the width of the bag is 9 inches.
The extra expanded fabric is made of the same 600D high-density polyester coated with polyurethane (PU) water-repellent membrane; hence the base of the Nayo EXP Backpack has the same water resistant protection as the rest of the outershell. The Nayo EXP Backpack is not 100% waterproof though, because the zipper seam fabric doesn't have any PU coating.
The rear compartment closest to the backside has dual zipper opening that allows this compartment to be opened longways like a clamshell on two halves. The rear compartment zippers are metal and attached to 3cm long metal pull tabs.
The rear compartment features a tall sleeve that measures 45cm high and 30cm wide so, it can accommodate a tall 17-inch laptop. The laptop sleeve is padded on the front and protected by the backside padding of the bag. The laptop sleeve runs all the way down the base of the backpack, which means the laptop will be in close contact with a surface when putting the bag down.
The base of the sleeve does have EVA padding, which is good for shock resistance. That said, having the base of the laptop sleeve run a couple of inches above the base of the bag would have been a better approach because it positions the laptop in a "suspended state", which is much safer for the laptop should you drop the bag on the floor accidentally.
On the opposite side of the rear compartment, there is a large pouch measuring 22cm tall. The pouch has an elasticated opening to keep things from falling out of it.
The two other main compartments are positioned towards the front of the bag. One of those compartments has the same dual zipper clamshell opening as the rear compartment but, instead of, opening longways it opens up sideways, just like a suitcase.
The material lining the bag is made of lighter denier than the outer shell and light blue in color, which brightens up the interior.
The single privacy mesh on the left side opens up via dual metal zippers so, you can easily slide one hand to reach for things without having to undo the zippers all the way. The single privacy mesh compartment has a raised lip around it designed to keep your things tucked in neatly so, things won't fall out when unzipping the bag.
The other side also has a privacy mesh but split into two separate pockets with their own zipper opening. The top mesh pocket has a height of 15.5cm, while the bottom mesh pocket measures 20cm tall.
Both mesh pockets have the same 28cm width and 2-inch usable depth since the mesh fabric material is not elastic. Anything bulkier than 2 inches will put unwanted stress on the zippers. The privacy mesh fabric is thick so, it feels strong and durable.
There aren't any side pockets on the Nayo EXP Backpack, other than side webbing straps (two per side) attached to plastic release buckles. The side webbing straps can be adjusted up 14cm to accommodate a rolled up gym mat or tripod carry case. If you require side pockets, check out the Almighty Backpack.
There are two grab handles. The top one measures 2.5cm wide and it's made of thin webbing material reinforced with a layer of PU leather across it.
The second grab handle on the Nayo EXP Backpack is located on the side so, you can carry the bag briefcase style like the Defensor Backpack. This grab handle measures 2.5cm wide, 14.5cm long and it has 1cm thick firm EVA padding, which is very comfortable in the hand. This grab handle also has breathable mesh on the backside of it so, the hand doesn't get as sweaty.
The shoulder straps measure 45cm along, 7cm wide and have a 0.5cm thick firm EVA foam padding. The shoulder strap padding is comfortable when resting on the shoulders and the S-curvature design helps the shoulder straps to stay close together.
There is a sternum strap though, which you can use to make the shoulder straps even more secure. The sternum strap can be adjusted lower or higher along the breastbone for comfort. The right shoulder strap has a small zippered pocket built-in large enough for credit cards.
Fit is good overall, although the shoulder straps are sewn at the top slightly close (5cm apart), which could be an issue for someone with a thick neck/broad shoulders as the shoulder straps amy rub against the sides of the neck. Those with necks measuring less than 40cm in circumference should be okay.
The compartment towards the front opens via dual metal SBS zippers (same as the rest of the bag) about three-quarters of the way. This compartment is quite roomy, running all the way down the entire height of the bag and, it features two elastic pockets and two pen holders. The pockets and pen holders measure 14cm high but the pocket on the right is slightly wider (12cm), while the pocket on the left is 10cm wide. The pen holders are 2.5cm wide.
Inside this compartment, there is also a long male USB cord, which is attached to an external female USB connector plug. This allows you to hook up a power bank so, you can charge your phone or other external devices on the go.
On the front panel of the bag, there is a zip pocket that spans the width of the bag and measures 30cm high. The front panel also integrates two forms of Nayo Smart branding, one being a heat printed etching and the other being a small metal tag with Nayo smart engraving.
The backside of the Nayo EXP Backpack is fully padded with EVA foam that is split into four sections to creates channels for air to flow and ventilate your backside. The back padding is very comfortable and it even integrates a zippered secret pocket that spans the width of the bag and measures 16cm high.
Across the backside, there is also a webbing pass through sleeve for attaching the bag over the handle bar of a suitcase. The weight of the bag when empty is 1.1 kg. You can buy the Nayo EXP Backpack from Nayo Smart.