Replacement brake block question

[Ranger]

I have just noticed the brake blocks on my Giant Defy are not in a carrier like on my previous brakes and it is now time to replace the brake blocks.

I would prefer to have the carriers as it makes the blocks easier to replace in the future, question is what do I call the carriers and where can I find them?

 

[Kestevan]

Cartridges. You should be able to buy a set of cartridges and blocks from any LBS
or wiggle etc.