racer coils

Is the racer coils solid on the bottom? Can they be used without a coil cover? I understand they are not epoxy filled and may be foam filled.. So curious as to what the bottom of the coils look like without covers. Thanks

Don't have a 5x10" yet, but the stock coil is open with coil cover on or off. My coil cover will never be put on my stock coils. As far as thr small OOR coil. Don't know, haven' had the cover off of it, the coil is closed on the bottom with coil cover installed. I beleive the 5x10 coil is closed I think with cover on (not sure when cover is removed) , unless I'm misinterpreting some of the pics I've seen via internet.

Small coil is epoxy filled.