This is a Hand Throttle Control believed to fit the Series 1, 2 and 2A Land Rovers as optional equipment. 

Looking at the Optional Parts Catalogue for Optional Equipment, it is difficult to be sure of the part number.

 

Looking at the picture in the Optional Equipment catalogue it is clear that: It is probably suitable for both Right and Left hand drive vehicles (RHD & LHD)

 

This listing does not include a lever and rod that will be needed to work the quadrant.

 

The lever is connected to the quadrant, the other end of the rod is secured to a lever. 

This lever is secured to the accelerator cross shaft by a pinch-bolt. 

Clearly this lever is essential for fitting, it would take a while to fiddle around and make up a suitable lever, as this is not available with this listing. 

The weight unpacked is 640g