There are many different styles of shackles. The standard dimensional format shackle gives you a high load capacity and compact size. With a smaller size body, it is produced from a formed stainless steel sheet and larger size bodies are from turned bar, coined at the ends. The pin heads are available in compact 'slotted' or 'coined' for finger or tool adjustment. Some of these pin heads come drilled so you can fit a securing wire properly.
Long dee shackles are similar to the standard dee, but have a longer internal length clearance so you can fit them to a longer or irregular shaped object. It gives you a greater distance between fixing points. An example of this would be attaching an outhaul line to a press ring on a sail.