What is the difference between HP 45 78 ink and HP 45 78 D ink?

I was looking on ebay for some ink and some people had it listed as 45 78 and others had it listed as 45 78d. I was wondering what the difference was. The listings for the 45 78d cost a lot more and I can not find anything that tells me the difference? Please Help.What is the difference between HP 45 78 ink and HP 45 78 D ink?
the 78D is actually the old coding for a low volume cartirdge.





The old version 9up until a few months ago used to be 6578d and the high volume was 6578a





Recently HP has changed all of their high volume/low volume codings to regular and XL.





To make a long story short an 78 is a 78d a 78XL is a 78A.





the difference is that a 78 and 78d both have 19ml of ink in them. a 78a and 78XL have 39 ml of ink in them.What is the difference between HP 45 78 ink and HP 45 78 D ink?
78 is sold seperatly


78D is the same thing sold at a slight discount because its packed with 45 and they need to denote that its NOT the following two items. (http://h20180.www2.hp.com/apps/Lookup?h_鈥?/a>





78XL( http://www.shopping.hp.com/webapp/shoppi鈥?/a> )





or





78+ ( http://www.shopping.hp.com/webapp/shoppi鈥?/a> )





All 78's should fit in your machine, the + and the XL just have differnt ink quality.