This handle is for an original Supernova chuck, sometimes mistaken for the Nova Scroll chuck, but it isn't. The first two pics illustrate the difference. 

Supernova says READ MANUAL... TEKNATOOL NOVA SCROLL... on the face and has 3 rings around the body that intersect the holes where the handle is inserted. 

There are no replacements  for the the Supernova handle and the G3 handle is not compatible. 

Supernova has not been offered for ten years +/-. Attached manual was published 2003. Notice no part numbers on page 5. Another attachment: Identify Your Nova Chuck.

The Supernova and consequently the T handle is obsolete but available from Timberly in NZ. See below.

Original Supernova

Original Nova Scroll

Original Supernova

Supernova Tee Handle (obsolete)

G3 just says G3 on the face of the chuck, has 3 rings around the body that intersect the slide guides, and uses T Handle SKU 48203.Z

 G3 Geared