>>>>>INCLUDES SCREW>>>>>INCLUDES SCREW>>>>>>ORIGINAL....... HK PART THAT WAS ISSUED WITH THE EARLY STYLE COCKING TUBE WHICH WAS STRAIGHT, NOT TAPERED ON THE END AND DID NOT USE THE HANGER AS THE HK33,HK91.............AND THE PTR91 USE TODAY................... THE CHANGE WAS MADE TO THE NEW STYLE TAPERED COCKING BECAUSE HK WANTED TO START USING PLASTIC FURNITURE AND A BIPOD...........THE HANGER WAS ADDED TO ADD STABILITY AND STRENGTH TO SUPPORT THE NEW BIPOD FOREND CHANGING THE TUBE ALSO REQUIRED THAT A CHANGE BE MADE TO THE FRONT SIGHT TRIPLE FRAME AND THE REAR BAND ON THE TRIPLE FRAME WAS ELIMINATED....... IT WAS THERE AS A GUIDE STOP FOR THE WOOD FOREND FRONT FERRULE . THIS ADAPTER WORKS WITH HK91,G3,HK33 BAYONETS FAMILY. CAUTION DO NOT LOOSE THE SCREW ITS A FINE THREAD METRIC EXOTIC SCREW AND A ORIGINAL REPLACEMENT IS HARD FIND . ALSO BE CAREFUL NOT TO CROSS THREAD THIS SCREW, HAVE CHECKED IT, ITS GOOD, START BY HAND ONLY. THIS ITEM IS VERY RARE.. correct; for HK41 SANTA FE