About 10-12 shell-on prawn tails per pack. Don't be fooled by their natural red colour - these prawns need to be cooked. One pack would serve two good sized main portions. This is a good-sized wild king prawn. They're from Argentina and are naturally red: they're raw and need cooking. If you are grilling these tails it's best to leave the shell on to protect the meat from the intense heat.  Because these are wild prawns processed at sea, you're getting them with the "vein" aka the intestinal tract. This is harmless after cooking but you will probably want to remove it from larger prawns. To remove the vein remove the shell or snip down the back with scissors to expose the back of the prawn. With a sharp knife run a shallow incision down the back of the prawn and rinse away the vein under cold water.