This is before I rebuilt the engine...
Had had rust in my engine from running Water Wetter for a couple of years - a bad idea. So I bought the Tefba on eBay and installed it after a backflush and going back to a coolant mix. Had the radiator overhauled as it was occluded with rust bits.
A few little bits showed up over time, then after a while, none. Removed the Tefba.
It's very easy to remove the top and clean the filter. A solid product.
If you want to install it without the backflush, IMO it'll be effective - you'll want to check it probably every time after you drive, until it has captured all the loose rust flakes in the engine.
Backflushing with this setup captured a mass of muck (old water wetter turns to peanut butter) and rust bits in the woman's stocking filter.