Andrea:
I googled Lopez Valve and downloaded a PDF file on it's uses and applications.
It sounds like it is exactly what is needed to prevent spills.
Tom:
The button tube sounds like a good alternative as well. Is it easy to clean around the entrance area?
Darrell

Stage 3, T3,N1,M0,SCC, Base of Tongue. No Surgery, Radiationx39, Chemo, Taxol & Carboplatin Weekly 8 Treatments 2004. Age 60. Recurrence 2/06, SCC, Chest & Neck (Sub clavean), Remission 8/06. Recurrence SCC 12/10/06 Chest.