This is the 5mm version of sp41, which is the xtr spec gear outer.
Very cheap here - black only unfortunately.
http://www.amazon.co.uk/Shimano-Spares- ... 65&sr=1-91
I bought 2 rolls of 7.5m for £5.99 each and got free postage. The same outer costs £25 from Parker international for the same length, so I'm hoping it's the right stuff!
Ah, found in grey here:
http://activesport.co.uk/shop/article_6 ... 976-5-2%26
Also these look pretty good die - drawn slick inners:
http://www.rocknrollbikes.com/road/cabl ... Hyperglide