MACHINED TEE'S
Lately though, more and more people are using the fitting without the ferrel, that is to say with a stick going thru the fitting in both directions. This actually is a beefier version of the Bobby Two Hole fitting, without Bobbys adjust screw or set screw. The disadvantage of this use is the fitting could get lost on disassembly.
When ordering, please specify what size spars and/or ferrels you will be using.