|Located next to Leo, maybe only on Channel 1|
The first time for us, he attached a requirement of 100 Mega Talts. Fortunately, we still have Mega Talts so we were able to complete the requirements. The reward from the box were 2 Veteran Experience Level G cards which gave 14 million experience points each. The second time we went for the exchange, we got the requirement of 30 Pieces of Emerald. Fortunately, a fellow clan member was kind enough to provide us with some and our reward from that exchange was 3 Honor Card A which gave 100 reputation points each.
Other requirements that we heard about from fellow clan members were 300 Ice Crystals and 50 Rholodite (?) Pieces. Those sound much harder to collect. We also haven't figured out what to do with the Certificates of Supply yet.