This is the "medium" Ultima head and shank fitted to the Sovereign handle.

The Sovereign Ultima Hollowing System enables the woodturner to create a myriad of hollow form shapes in both wet and dry woods thanks to its razor sharp cutting edge and articulating head and link system. It is equally effective on bowl grain work as well as end-grain project. It enables woodturners to produce hollow forms up to 16" (400mm)

The Sovereign Ultima comes fitted with an easy-clear head which allows waste material to be expelled quickly and efficiently. The turner can regulate the depth of cut - from ultra fine to heavy - thanks to the unique knurled "micro-adjust wheel" The cutter is manufactured from high grade HSS and only one third of it is exposed at any time. This means that it can be rotated through 120 degrees twice before it needs to be re-sharpened. Replacement cutters are readily available.

An additional link can be added to achieve extreme undercutting. If the link is removed then the Ultima can be used as a probe for straight sided hollowing.

A cutter sharpening jig is available as an optional extra. Manufactured from phosphor bronze the jig rotates freely within its sleeve and enables the turner to sharpen either with a diamond hone, bench grinder or ProEdge. The jig will also accommodate other full round cutters.

An optional Ultima finishing head can be fitted which will allow the turner to achieve a smooth surface finish. Other cutters are available that will fit to enable more advanced shape finishing.

The Ultima is available in two sizes. This one is the Medium size blade only which has a 5/8" shank to fit most metal handles including the Sovereign from Sorby (included). Blade length 18", and handle length 22".
Of course the handle can be used to hold many other Sorby tools and other tools. A side handle (extra) is recommended if you intend to use the Ultima for extreme undercuts on bowl rims and vessels.
Each Sovereign Ultima comes with a full set of instructions. Instructions are available for download from the Robert Sorby Website.