New RailBlock has 4 Types of Thread: 1/4", 3/8", M4 & M5 thread. Old one has 3 types: M4, M5 and M8 thread.

New wingnut design as follows (from 26th March 2012):

The railblock Rod Clamp can be mounted on any standard 15mm rods on DSLR Rig.

And there are 4 types of Thread: 1/4", 3/8", M4 & M5 thread, which are very useful if you like to DIY DSLR Rig.

Made of Aluminum.

4 Types of Thread: 1/4", 3/8", M4 & M5 thread.

1/4" thread: thread diameter is international standard 1/4";

3/8" thread: thread diameter is international standard 3/8";

M4 thread: thread diameter is 4mm;

M5 thread: thread diameter is 5mm;

Notes: rods, handle & arm not inlcuded.

Sometimes, the wing Knob would be blocked by your rig parts as follows.

So we recommend optional Freely Rotatable WingNut even if you Screw the Wingnut on.