If you use an Easy Vap to sublimate oxalic acid in honey bee colonies for Varroa mite control, you know that the factor that determines how quickly you can complete applications in an apiary is the number of hollow tapered silicone plugs available. It's easy for one person to have 10 treatments going at a time - more with 2 people - but Easy Vaps usually come with only 4 plugs. And the plugs don't last forever.
Only -$2.50 each - plus shipping costs if not a local Brandon, VT pick-up.