I have been using the pit rock type for years, never used anything else. I am however interested in:
http://www.trustproducts.com/
Saw it in Boots the other day, not cheap, but claims to work for several days, and is in a really tiny pot.
http://www.trustproducts.com/
Saw it in Boots the other day, not cheap, but claims to work for several days, and is in a really tiny pot.