Del, as mentioned below, all of the search coil for the 19 kHz FORS Gold Plus will interchange with the 19 kHz FORS Relic. The Relic assigned coils are black in color while the Gold + coils are white, but otherwise the same for the size and type. There are the:
FR/FGP-13 .. 5" round DD [size=small](current)[/size]
FR/FGP-24 .. 5X9½ DD open-frame [size=small](current that was to replace the different-size former solid-body 5½X10 DD)[/size]
FR/FGP-26 .. 5½X10 DD [size=small](currently listed in white for the FGP)[/size]
FR/FGP-26C .. 5½X110 Concentric [size=small](currently listed in white for the FGP)[/size]
FR-29 .. 7X11 DD [size=small](currently listed in black only for the FR)[/size]
FR/FGP-40 .. 12X15.5 DD [size=small](current)[/size]
As you know, the little round, and slightly over 5" diameter, DD coil is a killer in dense brush, building rubble and trash. The Relic w/5" DD is great at unmasking a lot of the low-to-mid conductors in a densely littered site. I have all but the larger coil for my two Relic devices, figuring I have the 'big coil' needs covered with the over-size on-hand for my CoRe and Impact units. Also, with the 'OOR' coil on my first-grab CoRe and 7" Concentric on my ready-to-go Impact, I have the smaller coil needs taken care of but can swap coils around on a Relic as desired.
For now, when I am mainly in the Coin & Jewelry Hunting season, I have my 5" DD and standard 7X11 DD on lower rods in my accessory coil tote, and keep an FR-24 open-frame DD on one of my Relic models, and the FR/FGP-26 Concentric coil on the other Relic. I just grab the unit/coil combo I want and need at different sites and conditions. The FR/FGP-26C is the ONLY Concentric coil made for the FORS Relic, and I wouldn't be without it. It is just slightly wider and longer than the new open-frame DD [size=small](5½X10 Vs 5X9½)[/size] but does provide me with the difference in performance a Concentric can accomplish over a DD in some trashy sites.
Oh, and I see you mentioned the solid coil cover available for the new open-frame DD coils. Yes, they are shown but I don't have any. I do have a solid-bottom coil cover for the 7X11 standard DD coils, and to be honest, all of the Relic Hunting sites I enjoy hunting that are often plagued with short, stiff weeds and brush and twigs, seldom cause me any problems with the smaller-size open-frame 5X9½ DD or even the newer 7" Concentric coils. The only time I have to put up with stiff, sticky weeds and such poking through a search coil opening when hunting is with the larger-size open coils. The 'standard' 7X11 and the bigger 13X15 and 14X15 coils.
The only coil I wish I had but isn't made, is a 7" Concentric for either/both the CoRe and Relic devices.
Stay warm, dry and comfortable, and the best of success to both of you down there during our colder weather back up here.
Monte