i use a flea comb (check through the hairs as best as i can ) while mike holds the suspected flead cat.
if i really think they have some though i will use any brand that looks safe.
i wish i knew which was the safest one to use.
they get in even if their indoor cats,through the screens...mostly the bottom part of the screen or where the cats clawed the screen leaving nice little claw holes for little bugs/mites? to get in,even from your shoes from outdoors.