I believe the Sawyer is a spin off from Renal Dialysis.Filtering kidneys is serious stuff.They work though,no matter how they are built.And the Sawyer is so cheap,especially when you consider how much it will filter.
I bought three of them a few years ago when I was flush with cash.One is in my GHB,one still in its packaging,and the other is in the ' emergency' kit in the pantry.The latter I played with by filtering rainbutt water ( no other treatment) and drinking it over a week.Took it to Spain last year for six months and used it when I was guiding anglers out in the countryside. It meant we carried less water, which is heavy.Nobody was poorly!
If they are made of string,then as you say,its magic string.

In three words I can sum up everything I have learned about life: It goes on.
Robert Frost.
Covid 19: After that level of weirdness ,any situation is certainly possible.
Me.