This milk strainer does one important thing really well: it strains milk. It didn't come with any instructions, but I managed to figure out its operation: stainless steel strainer goes in first, then a paper filter, then squeeze and insert the "spring" to hold down the paper filter. It's got a large enough funnel that I don't often find myself splashing milk, and a large enough exit that I almost never have to wait for it to empty.
Do note that if you want to put your milk into canning jars, you'll need an adapter that steps down the size of its exit; this is sized for milk storage cans. Hamby does sell those adapters, and I've now got one on order.
The major downside I've found of this strainer is that the stainless steel it's made from feels a bit thin compared to a lot of the other stainless steel dairy equipment I've bought from Hamby. It's thinner than my milking bucket, my storage cans, and their lids. Hopefully it'll hold up over time, but it hasn't gotten dented or bent yet.
It strains well enough. I don't much care for the little wire that you fit in to secure the filter - pretty low tech. I was hoping for a little better quality but it works okay and I will use it.