Named after a geometric shape (polyhedron), the Fenruien Polyhedron backpack stands out from outer laptop backpacks for its polyhedron-shaped front panel, which is reminiscent of a turtle shield. While not as hard as as a turtle shell, the front panel of the Fenruien backpack has a semi-rigid flexible construction similar to a suitcase. The front panel shield is made of textured solid plastic (PC and ABS), which is irregularly shaped so, it is not flat. It is also watertight so, water beads and rolls off of the front panel.

 

As well as being irregularly shaped, the Fenruien front panel has a beveled design with the bottom section being slightly wider (31cm) than the front section (29cm wide). The front panel measures 48cm high and, it's hollow internally with a 4cm depth to help shock absorption.

The Fenruien 25 litre backpack has waterproof zips with two long aluminium metal sliders that double as pull tabs. The zip sliders measure 4cm long and have a tiny hole opening that could be used to loop a security cable around. The word "Fenruien" has been carved into the black anodized metal sliders. The zippers don't have any branding on them but, according to the spec sheet, they are SBS zippers. The zips slide smoothly without jamming.

The base of the Fenruien backpack, as well as the sides have been coated with the same rubbery material as the zippers, making the Fenruien backpack virtually waterproof from the front. You won't need to use a rain cover with this backpack since the waterproofing extends all the way to the rear access compartment. The rubbery coating not only repels water, it also makes the backpack more resistant to scratches, especially the base, which is the area of the backpack that takes a beating the most.

More Fenruien branding can be found throughout the backpack, including the metal shield badge on the top front of the backpack, as well as the grab handle and the front side of the right should strap. Speaking of shoulder straps, they have a robust construction, covered with waterproof material on the front and breathable mesh fabric underneath. The shoulder straps measure 45cm long and are beveled with the top being much wider (8cm) than the bottom of the shoulder strap, which measures 5cm wide. The shoulder straps are very comfortable, thanks to the closed cell foam padding, which is approximately 1cm thick.

The shoulder straps integrate an adjustable webbing strap with plastic buckle for sternum adjustment, as well as a single webbing loop and a small zip compartment (8cm long) which is large enough for credit cards and similar items. The backside of the Fenruien backpack is fully padded with a seamless piece of padding covered with mesh fabric. The back padding is open cell and feels a bit too soft when carrying heavy loads. The mesh fabric does help the back padding to be more breathable, although split padding is always better for minimizing a sweaty backside. On the backside, you will also find a large secret zip pouch.

On the backside of the Fenruien backpack, there is also a pass through trolley sleeve, as well as a secret compartment, which measures 15cm high and, it's fairly roomy so, you could store a small book inside it. On the sides, there is a side pocket that measures 18cm high and 9cm wide. 
The side pockets are low profile, compact and elastic to help expansion. The side pockets are on the small side so, the most you can fit in the side pockets is a 500ml water bottle or small tripod. The side pockets also have a zip with a single metal slider built-in, which is useful when you don't want the side pockets to expand.

Right above the side pockets, there is a TSA combination lock on one side and a charging port above the other side pocket. The combination lock has a TSA keyhole, three wheel locks, two locking bars and four slots for locking up all four zip sliders. The locking bars are spring loaded and they open and close by sliding the TSA keyhole left and right.

The combination lock measures 9cm long, 3cm wide and 1cm thick and, it's built-in to the backpack; hence it cannot be detached. The preset password for the lock is 0000. To change the password, you have to push the reset button and dial the combination password you want. Once the new password combination is entered, you push the slider left or right until you hear the reset button pop.

The external charging port is another useful feature found on the Fenruien Polyhedron backpack. It is built inside a low profile plastic housing that integrates two female charging ports (USB-A and micro USB), which are protected by a hard plastic flap. The external charging port is attached to a 60cm long non-detachable plastic cable with dual jacks (USB-A and micro USB). The charging cable is accessed via the front facing compartment and, it is located inside a small zip pocket, which allows you to neatly tuck in the cable when not in use.

The front facing compartment is divided into two storage areas via a privacy mesh (with dual zip sliders). The total depth of the front facing compartment is 14cm approximately; hence you can store bulky items such as a pair of working boots or even a cycling helmet. There is also a small lip running around the edge of the zip to help keep things neatly inside.

On the privacy mesh side of the compartment, there are two small fabric side pockets (15cm long/ 7cm wide), as well as a large zip pouch, measuring 26cm high and 22cm wide. On the opposite side of the privacy mesh, there is a zip mesh pouch (20cm wide and 18cm high) and two open pockets, which measure 13cm wide and 14cm high. There is also a detachable plastic keyring attached to a 12cm long thin webbing cord.

The rear facing compartment of the Fenruien backpack also has a 180 degree vertical opening. Inside, there is a laptop pocket, as well as an organizational panel (22cm wide) with multiple pockets, including two open mesh pockets that measure 13cm high. There is also two open pouches measuring 22cm high and 17cm high respectively. The laptop pocket compartment measures 45cm high, 28cm wide and 6cm deep; hence you can store a thick old laptop in there or an A4 ring binder.

The laptop pocket has an opening at the bottom of each corner for running cables, as well as a velcro flap to fasten the laptop pocket. The velcro flap has a zip pocket built-in, which measures 16cm wide and 14cm high. The laptop pocket cotton material has a geometric-like pattern on it and, it's thin without any padding. That said, the laptop pocket is sewn 1-inch above the bottom of the backpack, which should help minimize bottom impacts.

On top of the Fenruien hard shell backpack, there is a large and thin grab handle, measuring 15cm long and 0.3cm thick. The grab handle is made of flexible plastic rubber and has no foam padding in it. That said, the rubber construction is soft and smooth so, it doesn't dig into the hand. The suitcase style openings of the Fenruien backpack compartments makes packing and unpacking the backpack very easy and convenient. The backpack is mostly lined internally with basket weave fabric, which is durable and padded around with EVA rubber. Total weight (empty) is 1.5kg. You can buy the Fenruien turtle shell backpack from Zinmark and get $10 off using code GADGETFANS10.