High quality cap bolt washers. Available in 3 sizes that can fit M3/ #4-40, M4/#8-32 or M5 threads 
Choose from Red, Blue, Gold, Green and Black! 
Sold in packs of 10                                                                                                  

Material: aluminium 6061-T6 (anodized)
Out Side diameter: 12.0mm
Inside diameter: 4.5mm 
Bolt: M4, #8-32

Out Side diameter: 10.0mm
Inside diameter: 3.5mm 
Bolt: M3, #4-40

Bolt: M5,