"As it's important to know the rating for a particle filter I spoke to the supplier who confirmed this item is 5 microns. It is such good value. Hopefully Screwfix will add this to their specification."
"Out in Greece this type of filter runs out at just under £9 although filters of 25 microns are around the same price as Screwfix but this Scrtewfix filter appears to be 5 microns. I say appears to be because it was rather hard to track down the specification, This is not a complicated product. It either filters well without too much drop in pressure or it doesn't. I think that it does and in a situation where the road seems to get dug up all the time, it is especially good to have - but at this price you can afford to experiment and just see what gets held up by the filter over 6 months - it's amazing."