The Rucksack Other Arms from the British army and the Osprey Porter are both “single” compartment backpacks where you can hide the shoulder straps. This allows you to use it as a hand carrying bag. Both the backpacks are not very high compared to their width.
The Osprey Porter. Source: expertworldtravel.com/osprey-porter-vs-farpoint-backpack-travel
If you spend most of your time carrying your luggage at your back when hiking or going to the woods and mountains, then a real backpack is most suitable. If your backpack spends most of its time in a luggage compartment of a bus, train, air-plane, mini van, taxi etc. then a single compartment bag with no extra straps or side pockets is more suitable. This setup comes close to a suitcase that you carry on your back.
In Thailand it can be hot and sweaty. A light weight thin piece of fabric can absorb that sweat around your head of wrist. On a motorbike you can use it as a scarf to protect your mouth from flies and dirt. In busses it can be chilling cold because of the airconditioning. Then you can use it as a scarf to give you some extra warmth. When sleeping in a bus or hostel you can use it as a blind coffer for your eyes. Also suitable for naughty sex games.
When you are traveling you need to wash your clothes sooner or later. Luckily you can find many laundry services in Thailand. They will wash and dry your dirty clothes for 40 to 200 Thai Bath. But sometimes you just want to wash one or two items or you just stay one night in a place. Then it is an option to do a quick hand wash in a bucket or in the bathroom sink. For these situations it is super handy to have your own small rubber bucket with you. It is light and it doesn’t take much space in your suitcase or backpack. In case you don’t have soap with you you can always buy some in a small package at the 7-Eleven. Or you can off course use some shampoo or shower gel.
The Dutch / Belgian military rubber bowl will stand right up by the pressure of the water what is inside. The bowl isn’t that big (approx 4 litre) but it is large enough for a T-shirt, a pair of socks, some underwear and a short. Just let your laundry soak in the water with soap for a few hours and then wash the soap out of the laundry under running water from the tap.
The Polish WZ89 army backpack (aka Frog or Puma camouflage) is a cheap and simple backpack. Just a big sack with two straps on it. It was in use in the Polish army from 1989 and until 1993. The typical camouflage pattern is called the Zába Pattern, which in polish for Frog. On military surplus store websites it is also called the Polish Puma camouflage pattern. In Germany this camouflage pattern is often referred as Pumatarn.
The bottom is protected with a rubber (PVC) coating. So when you place your bag in a small puddle of water or in some wet grass not all your stuff is totally soaked. For a better protection it is wise to use a big plastic bag inside the backpack itself since the fabric is very thin and not very water resistant. In military surplus stores you can also buy special water resistant laundry bags.
The top side of the pack has two drawstrings, one on the very top and one a bit lower down the body. The lower drawstring allows for loading to regular capacity, similar to a normal rucksack. The top drawstring allows you to expand (overload) the pack to the size of a big backpack. Keep in mind that there is no padding on the shoulder straps. So if you you load up on weight it’s going to cut into your shoulders and may hurt. The big top flap can be closed in two different heights; two triglides on the bottom or two triglides half way the pack.
The rucksack is constructed of very flexible material and doesn’t have a rigid frame. This simple construction gives very little wearing comfort. However this also makes it ideal for packing and compressing your luggage down to a small package and in the same time it also allows you to expand the bag to carry a much larger load. It is also possible to fold the bag down and take it with you as an extra bag in your main luggage. Since the weight of the pack is only 0,75 Kg it is not that much extra.
Other comparable designs.
There is also an improved version of this backpack with a different camouflage pattern (WZ93 Pantera) and stronger materials. The M93 Pantera camouflage backpack. The fabric of the M93 backpack is waterproof and the name tag is stronger and equipped with a better plastic window.
The much bigger and heavier French F1 65 liter military backpack might have been the inspiration for this design. That bag is also more like a duffel bag, comes also with a rubberized bottom, and is also closable at two different heights. But that bag is made of much heavier canvas and the rubber is thicker and comes higher from the ground. This makes the weight of this pack going up to 2,15 Kg. The backside of the pack has a padded back support in a triangle form, the shoulder straps are padded and the pack has a simple belt to let the weight rest at your hips. These features makes this backpack / duffel bag quite comfortable to wear. More info in this special blog about the French army F1 backpack.
Many people regard a soft backpack without any back support or padded shoulder straps as a ridiculous idea and the worst design ever. However the famous (military) backpack company Berghaus made a similar backpack The Berghaus MMPS Grab Bag. This bag has also one main compartment without side pouches. Only the cover lid is a little more sophisticated with a pouch behind a zipper and some webbing for attaching extra gear. This bag is also meant as an extra light weight bag that you can take with you in your main luggage.
Tortuga Backpacks are designed by two travel veterans. After a backpack journey they noticed that all backpacks and other bags and suitcases have their own advantages and their own disadvantages. They decided to develop their own backpack. Main feature is that you can open the backpack in the same way as a suitcase. This makes the backpack more suitable for travelling. Most backpacks are designed more for hiking than for travelling and open therefore from the top.
They don’t sell their products in physical shops but on-line only.
After a little research it turned out that Osprey also has a backpack what can be opened from the front instead of the top. Their backpack is called the Osprey Porter 46. The following youtube movie compares these two.