Phoz and JBoyd is both wrong... 10mm is the aprox size before shrinking. The size can diff from lot to lot, but should never be under 10mm. I have measured outside dia to ~11,4mm. Wall thicknes is 0,3mm,(not close to 2mm as JBoyd think) so inner dia on the tube I have is 10,8mm. It would be nice if HobbyKing corrects the wrong information in the description("Diameter: 14mm ")
Red color a bit faint, but ok. It shrinks to about 6mm diameter, maybe 5mm too. When hot, you can help it with your fingers taking up shapes of underlying edges too. Ends of the shrunk tubes quite hard, they hold well.