Electronic flea killers

[mrsxllifts]

We think we have a few of the critters trying to find somewhere warm in our carpets. Cats been done and there is none on him but we keep getting the telltale ankle bites.

Have seen these electronic flea things, think they come with sticky disc things. Has anyone used one and are they any good? Am trying to avoid sprays and bombs due to my allergies to stuff like that but if needs be, we can use them as a last resort.

Thanks