What kind of processing is the '4 rounds of PU coating' mentioned in the bag description?
It is a waterproof treatment that applies polyurethane four times to the inside of the fabric to prevent everyday rain or water droplets from easily seeping into the bag.
The number 4 refers to the number of times the waterproof membrane has been layered. PU coating is a processing technique where polyurethane resin is thinly spread on the inside of the fabric to prevent water droplets from seeping between the threads. By repeatedly applying a thin waterproof membrane four times, it achieves basic everyday water resistance to block sudden rain or snow.
![Symmetric Codura Backpack #2 [black]](https://img.hmmm.pub/brands/ryoo/products/e19603cf-b936-427b-96ed-4e55a39faa59/500.w640.webp)
![Symmetric Codura Backpack #2 [black]](https://img.hmmm.pub/brands/ryoo/products/e19603cf-b936-427b-96ed-4e55a39faa59/501.w640.webp)
![Symmetric Codura Backpack #2 [black]](https://img.hmmm.pub/brands/ryoo/products/e19603cf-b936-427b-96ed-4e55a39faa59/302.w640.webp)
![Symmetric Codura Backpack #2 [black]](https://img.hmmm.pub/brands/ryoo/products/e19603cf-b936-427b-96ed-4e55a39faa59/400.w640.webp)





















![Symmetric Codura Backpack #2 [black]](https://img.hmmm.pub/brands/ryoo/products/e19603cf-b936-427b-96ed-4e55a39faa59/0.w640.webp)