The extension glasses for the Voopoo UForce tank work a little differently to most. Due to the shape and size of the tank for any of the extension glasses to fit you will also require an extension chimney and for the larger glasses you will require 2.
So for the Voopoo Uforce 5ml extension glass only 1 extension chimney will be required. As for the Voopoo Uforce 5.5ml and 8ml glasses you will require 2 extension chimneys.
These glass will only fit the Voopoo Uforce Tank
1 x 5ml Bubble glass + 1 Adaptor or
1 x 5.5ml Glass Tube +2 Adaptors or
1 x 8ml Bubble Glass +2 Adaptors