Self-locking stainless steel allen head D shackles. ideal to link chain and anchor. On the halyard, avoid damage to the sails. Grade 316L stainless steel. Self-locking shackle with allen head pin D forged in grade 316L stainless steel The pin is locked into one of the indentations The head of the pin does not stick out from the shackle body and thus eliminates any risk of snagging No risks of loose due to vibrations Outstanding working and breaking loads