Sorry for the late response guys. We have been overseas at IWA in Nuremberg Germany, the SHOT SHOW of Europe.
The SaberTube (tm) is between the MilSpec Carbine Length Buffer Tube and the Rifle Length Buffer Tube. Here are a couple of photos for comparison.
The Top one is the SABERTUBE(tm) with our BAD-LBS Lightweight Butt Stock. The Bottom one is a MilSpec Carbine Length Buffer Tube with our BAD-LBS-MIL Lightweight Butt Stock for MilSpec Buffer Tube (or A5 Length Tube).
The first version we released is the ultimate lightweight version with out the need for Castle Nut nor the End Plate. The only catch is you need a lower receiver with a self retaining rear takedown pin detent spring like our BAD556-LW Lower.
If you do not have a lower with that feature then you need to wait for another version of the SaberTube(tm) cut for a End Plate with build-in QD (limited rotation). They will be ready for release through Rainier or Revolver in a week or so.
If there are any questions here that doesn't get answered right away please PM or email us. It is difficult to cover all the forums, social media accounts, emails, phones, etc. Until we have someone dedicated to the forums I would be happy to answer any questions.
Thank you.