Passive wash basket mounted lit filter filters
These were probably less effective than the filters where the water was actually pumped through a filter, by far the most effective filters ever in the top load automatic washers were the self cleaning back flush filters that whirlpool used in their belt drive machines.
Whirlpool went to the basket, mounted ones because they were less costly but most of all it made the machine much more reliable because the back flush filters could be ruined by hard water and no phosphate detergent so it reduced service calls quite a bit.
Gordon, Kenmore 64 claims at the basket mounted filters on belt drive machines actually worked quite well. I was always a little skeptical, but he claims to have proven that they really did catch a lot of lint that would be thrown off when it went into spin and drain.
Of course the little tiny filters that may tag dependable care and later whirlpool direct drive top loaders used were absolutely useless and were really just there so that they could claim that it had a lint filter. Speed Queen also had a passive filter under the basket which looked absolutely useless, as did many WCI top letters.
John L