As Kieran says, 'pointless'. At 2.5 inches high, it doesn't seem much point. I'd also be very reluctant to put a hot drink into a collapsible metal cup.
Martin
Sometimes your joy is the source of your smile, but sometimes your smile can be the source of your joy.
Nice for the odd tipple though when sharing a bottle. I have seen these at the size of a standard household mug.
Depends what you need the mud to do. If it's only to drink from it needn't be too big or elaborate. If it's for boiling water in I would look at either the tatonka or something similar. Personally I'm not keen on aluminium especially on an open fire.