I just placed an order for those stoppers. Again, thank you Solid for that suggestion!
FYI...if anyone else places an order with them for stoppers, it was posting a high shipping rate for USPS Priority and even worse for UPS. I called the company and they were happy to agree to shipping via First Class mail which reduced the cost of mailing by nearly half. Now my entire order, including shipping, is cheaper than the cheapest shipping method shown.
"Aquarists are a brave lot. We mix water and electricity every day."