I'm aware a lot of pumps have a clear section already but I'm not really sure on standards.
Having (a long time ago) been sold "fuel hose" from a factor that melted a week later due to the petrol eating it, I tend to be a bit wary. Assume it was coolant hose, quickly replaced from elsewhere.
For what its worth I've ordered a small length of three sizes as I plan to warm it in some hot water then pop it on so its a reasonably tight fit before any clips, better that way I think.
http://www.ebay.co.uk/itm/231018295816" onclick="window.open(this.href);return false;
http://www.ebay.co.uk/itm/261205830398" onclick="window.open(this.href);return false;
http://www.ebay.co.uk/itm/221095794926" onclick="window.open(this.href);return false;
The smaller sizes will come in handy as its useful to keep some, if nothing else they may be ideal washer tubing lengths.
I do need some and also I plan to keep a small length attached each side of a primer 'bulb' as a handy tool for emergencies and general fuel work where required too.