anyone ever used any of these or know anything about them? Lowers/uppers, etc.

http://www.tacticalinc.com/ar15-lower-receiverbrwith-stbasuptmsup-installed-p-1162.html

Thanks in advance

Never approach a bull from the front, a horse from the rear or a fool from any direction. - Billy the Kid.

Democracy is two wolves & a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote.
- Benjamin Franklin