Designers seem to love convertible, multifunctional backpacks, as evidenced by designs like the Glyde Gear Fly and WalkBag. They don't mind the occasional convertible jacket, either – just look at the weird-but-real JakPak. The Vamoose jacket is both. Similar to the Xip3, the jacket transforms into a backpack when not needed for rain and cold.
Because it's built with name-brand eVent fabric, we'll think of the Vamoose as a waterproof-breathable jacket that moonlights as a day pack. The three-layer jacket is equipped with a large external pocket for carrying small items like sunglasses, water, sun block, snacks and cell phones. Within a few seconds, that pocket turns into a main backpack compartment when the jacket is folded into itself and reversed into a small, 3-liter rucksack. You have a jacket to carry the basics when it's cold, windy or rainy and a backpack for when fast-moving mountain weather changes the outlook to warm and sunny.
In addition to the main external pocket, the pack has strap pockets for additional small items and a bungee cord for strapping things in.
As a jacket, the Vamoose appears to be a quality water/windproof design. The 750 g (26.4 oz) jacket features a built-in adjustable hood, taped seams, storm flaps and adjustable cuffs. It's cut extra long for added protection and is roomy enough to layer under.
The Vamoose jacket isn't a bad idea for short hikes and outings where there's a chance of rain or cooling temperatures. Hikers would usually prepare by packing a water/windproof jacket into a separate backpack, so the Vamoose could eliminate the need for two separate pieces of kit while maintaining that level of preparation. Longer, more gear-intensive outings will require more space than the small Vamoose pack provides though.
In addition to the jacket, Vamoose also offers a poncho. The poncho features the same eVent construction and backpack transformation as the jacket, but it can also be stretched into a flat sheet and used as a tarp, sunshade or gear cover. The video below shows it being switched over from shelter to poncho to backpack, and also shows the jacket in action.
Both the jacket and poncho retail for £285 (approx. US$450) each.
Source: Vamoose via Outdoors Magic
The video answers your concerns. The jacket's pocket becomes the backpack's main cargo room.
So it's cold, you put on the jacket, zip open the jacket's single pocket and fill it with lip chaps, extra clothing, snacks, etc. If the weather turned and the sun comes out, you take off the jacket and convert it into the backpack. Zip open the backpack, and rummage among the lip chaps, extra clothing, snacks, etc. for your sunglasses, and put it on. Zip close the backpack and swing it onto your back and go on your way.
Conversely, it's sunny. You zip open the backpack and put water, snack extra clothing etc in it. Later on, a light rain falls on you. You take off the backpack, convert it into the jacket, and put it on. You zip open the jacket's single pocket, take out some snack for some energy, and go on your way.