What this kit is built like
Neither of these is a lightweight item and neither pretends to be. The sleeping bag cover is a stated 1,300 g (45.9 oz) or so. The dry bag is a stated 1,180 g (41.6 oz) or so. On shelves where the competition is counted in tens of grams, that is a different category of object — built for hard use and a long life rather than for a pack budget, which is a legitimate brief as long as you know that is what you are buying.
The cover is described where it counts
The bivy cover is a three-layer laminate with a stated 5,000 mm (196.9 in) water column, a 225 by 85 cm (33.5 in) cut, a 40 by 8 cm (3.1 in) packed size and an integrated hood adjusted by elastic and hook-and-loop. Its closure gets a full description: a two-way side zip with an overlying storm flap on press studs. That loose cut is the right idea, because a cover that squeezes the bag inside it compresses the insulation it is supposed to be protecting.
The word that does the work of a number
The membrane is called breathable and no figure is published for it, and no test is named either. On a sealed laminate wrapped round a sleeping bag, breathability is precisely what decides how damp the inside is by morning, and it is the claim this site flags rather than repeats. No denier and no seam treatment are published either, so the two properties that determine how long the cover survives are both absent from the page.
A note on the dry bag
It should be said plainly: the Mil-Tec dry bag is a rucksack. It has padded shoulder straps, a chest strap, a ventilated back panel and MOLLE webbing, and this site does not cover what is worn on the back. It is here as a comparison point, not as a recommendation. What it does publish is useful anyway — 250D PVC and polyester, roughly 35 liters, dimensions of about 57 by 29 by 20 cm (7.9 in) and a weight to go with them, and a claim of brief submersion rather than heavy rain. What it does not publish is a seam treatment or a water rating to stand behind that claim.
