I don't use anything. I'm very leery of flea products as they are poison and would only use them as a last resort. Just my personal feeling on the matter. In the warm weather I keep a close check on them, do a daily comb for fleas etc. They have not had any on them. I always regularly wash their bedding and vacuum daily.
"Until one has loved an animal, a part of one's soul remains unawakened." ~ Anatole France