I have just purchased a Palm APC as an upgrade for my Astral Greenjacket. The APC is a fat anodised aluminium O-ring for your PFD chest harness providing an easy to recognise attachment point.

Similar ring systems have been used in the climbing and arborist world for some time as an easy way to clip into and as part of rope setups.
Although many PFDs with rescue belts come supplied with a steel welded ring the APC is bigger, easier to see and as a result will be easier to clip into.
The APC can be found online for around £10.
One of Whetman’s Bait rings is also on its way after ordering one from the site. It will be good to compare the two. Not sure on the APCs strength rating. The Bait Ring has a break strength of 25kN.