Practical in Daily: Internal tooth star lock washers is good for quick fixes and make a repair,apply a spring force between the fastener head and the substrate,causes the washer hard against the substrate and the bolt thread hard against the nut or substrate thread,to produce greater friction and rotational resistance. Premium Material: Internal tooth star lock washers are made of 65Mn manganese steel,sturdy and durable,without deformation,abrasion and corrosion resistance,high and low temperature resistant and durable,easy to install. Star Lock Washers Assortment: Quick speed locking washers with 7 most used sizes,M39 (60pcs),M412 (60pcs),M5*12 (60pcs),M6*14 (50pcs),M8*18 (50pcs),M10*20 (40pcs),M12*25 (20pcs),you can choose different size according to your needs. Widely Application: Internal tooth star lock washer widely used in machinery equipment,lawnmower,motors,cars,trucks,trailers,toys,bikes,RVs,boats,pumps,furniture,electronic equipment,automobiles,sports equipment,and also a good accessory for industrial production. Easy to Store: All 340 pieces washers are classified and stored in a transparent plastic case,it is very easy for storage and searching,each size is individually separated in the storage box for easy selection,7 sizes meet your different needs,which is convenient to find and take,efficient and fast,and not easy to mess.