SO far I have used Provident, JM Bullion, & SD Bullion. Bought some acrylic bar & coin capsules directly from Air Tite. One time the Post office lost a gift card because it fell through one machine at the Honolulu airport sorter down into the machine underneath it which sends letters to GUAM. If eventually arrived but had a hard time trying to call the Guam post office because they are across the international date line and never seem to answer the phone!