5000mm means that when there is a pressure of 5000mm water column on the surface of the jacket, that is, when 5 m water column is pressed on the surface of the jacket, it will not be waterproof.
Waterproof index, their unit is millimeter water column pressure. Generally speaking, when the water column with the height of 10000 mm presses on the fabric, and no more than 3 drops of water seep from the fabric within 24 hours, then we think that the waterproof index of this garment is10000 mm.
Extended data:
The higher the waterproof index, the stronger the waterproof performance, and of course the higher the price. What index coat to choose depends on your actual needs.
If it is only used for intercity travel and daily outdoor wear, the waterproof index is 3000mm to 5000 mm.
If it is a quasi-professional outdoor hiking, camping or crossing, waterproof underwear of 6000mm to 8000mm is enough.
If you need to go to an environment with difficult natural conditions for professional outdoor activities such as mountaineering and exploration, you'd better choose an assault suit with a waterproof index of 10000mm or more.
References:
Baidu encyclopedia-jacket