Our Chassis tube fits all JÄGER Chassis Systems as well as most other threaded end chassis systems and buffer tube adapters.  The Chassis Tube has the same external dimensions and thread pitches of a standard 5-position AR buffer tube,  but has a reinforced interior for added strength and durability.  The walls of this tube are thicker than standard AR buffer tubes and as a result WILL NOT ALLOW FOR THE INSTALLATION OF A STANDARD BUFFER/BUFFER SPRING ASSEMBLY.  The package comes with an accompanying castle nut.