KAK INDUSTRY AR15 SIG SB-15 DEDICATED PISTOL BUFFER TUBE THIS TUBE IS PERFECT FOR YOUR SIG SB-15 ARM BRACE PISTOL BUILDS DEDICATED TUBE DIAMETER FOR A PERFECT FIT ON YOUR SIG SB-15 ARM BRACE THIS TUBE EXTENDS FROM THE RECEIVER 8.45 FROM THE ENDPLATE TUBE WEIGHT 7.8 OZ MILITARY HARD ANODIZED BLACK FINISH KIT INCLUDES KAK SIG SB-15 PISTOL BUFFER TUBE, MODIFIED ENDPLATE, STANDARD CARBINE BUFFER, CHROME SILICON CARBINE SPRING SIG SB-15 ARM BRACE NOT INCLUDED FOR THOSE WHO HAVE NOT USED THIS TYPE OF TUBE BEFORE, NO LOCK NUT IS REQUIRED AS THE TUBE SHOULDERS ITSELF ON THE RECEIVER. ALSO THE ENDPLATE MUST HAVE THE ALIGNMENT TAB REMOVED OR GROUND DOWN TO ALLOW THE TUBE TO SPIN FREELY THROUGH IT. KAK INDUSTRY QD PISTOL VERSION ENDPLATES ARE AVAILABLE FROM US DIRECTLY AS WELL JUST ASK FOR PISTOL VERSION.. THESE ARE THE NEW DEDICATED SIG SB15 ENHANCED TUBES THAT FEATURE A DEDICATED DIAMETER FOR THE SIG SB-15 ARM BRACE, EXTENDED LENGTH FOR MORE SUPPORT ON YOUR ARM, LARGER SHOULDER DIA FOR INCREASED LOCKUP SURFACE FOR EXTRA STRENGTH AND STIFFNESS. THESE ARE HIGH END WARFIGHTER GRADE PISTOL TUBES THIS BUFFER TUBE SYSTEM IS PATENT PENDING13.1 OZ TOTAL WEIGHT