Quoting lolajessup:" I can't tell for sure but it looks like there two kinds. There's a canopy cover hitch looks like a blanket ... [snip!] ... and top. Those are $80. That's a good deal for the canopy style ones but I can't tell from te pic if it's only over the top."
Her photo shows the cover on the seat too which will interfere with the straps. Basically if it's not touching the straps or the base/seatbelt its good. (Unless of course you get into the whole fire retardant thing, but once you wash a cover there is no retardant left on it anyway).... As a general consensus from CPST's, the canopy covers and the shower cap covers are fine. Actual seat covers are not.