Didamx 160Pcs M6 M8 M10 M12 M14 M16 M20 Flat Ring Copper Metric Sealing Washers Assortment Set

I bought these washer to use in creating copper jewelry and they are perfect for that. However if you are planning to use the washers for an application where you need to comply with ISO 7089 standards you'll need to be careful because these don't comply with the "M" numbers advertised. The documentation with the box looks pretty accurate as far as the outer diameter dimension and the thickness, however it's completely missing the inner hole diameter dimension. And the M number may be completely inaccurate.For example, according to ISO an M20 has (approximately) an inner hole diameter of 21mm, an outside diameter of 37mm and a thickness of 3mm. But the washers in the box which are labeled M20 have the following approximate measurements: Inner hole 20mm, outer diameter 26mm, thickness 1.5mm.The photos supplied with the listing are very good which is why I didn't add more. But pay close attention to those photos to ensure these are what you are looking for.

Needed some copper washers for sealing bolts on an injection pump. These were just right.

Good item!!! Fast shipping!!!

A number of obviously defective parts mixed in. Most look OK.