The 2" Dakin Barlow shown below with the top of the 2.4X Barlow unscrewed from the bottom. The Barlow glass is in the bottom portion,
The 2" 2.4x Dakin Barlow assembled below for use with a 2" eyepiece.
The 2" Dakin Barlow shown below with the top of the 2.4X Barlow removed and the bottom screwed directly into a Brandon 48mm eyepiece, resulting in an approximately 32mm EFL.