These are long M10 connector nuts in stainless steel and large diameter heavy duty stainless steel washers.
This idea was origionally developed by Mike Satur machined from stainless steel hex with a blind hole to protect the screw . This would enable the easy removal of the cat or exhaust when required. Now these off the shelf nuts are made to connect M10 rod and are a cheaper way of buying an almost identical product.
It is recommended that zinc plated bolts are used as well rather than stainless steel bolts as they can work harden and seize..which defeats the object.
NOW SUPPLIED WITH M10X35mm BOLTS.
A set of six is supplied in a kit and can be added to any exhaust fitting kit for this extra amount.