Actually we sell numerous toys designed to help improve kegel muscles - best one is from a company called Tantus (USA based I believe) they make something called feeldoe
There are a few other versions referred to as the Cher or the Infinity.
So obviously the bulbous end is inserted into the vagina and then you can either use it as a strap on or holding it in place while you walk around the house ( I wouldn't do this in public) improves the strength and tenanciousness of the kegel muscles.
I don't have one simply because I think the other half would freak if he came out one morning and I had an erection poking through my robe. Thinking about it though.
We sell alot of these to couples who have just had kids - local doctors have started advising women to get them after a natural chilbirth to help with regaining the strength of vaginal muscles, they're even more popular then Tens machines now