Dog Tooth Washers

Used in many joints where restricted movement is required such as roofing joists, Newall posts on decking etc. Can be used with many types of bolts and fasteners, in particular carriage bolts.
Zinc coatings prevent oxidation of the protected metal to create a longer-lasting finish. It does this by forming a barrier and by acting as a sacrificial anode if this barrier is damaged.
Zinc oxide is a fine white dust that (in contrast to iron oxide) does not trigger a breakdown of the substrate’s surface integrity as it is formed. The zinc oxide, if left intact, can act as a barrier to further oxidation, in a way similar to the protection afforded to aluminum and stainless steel by their oxide layers.