You're able to place a Laser Designator into a Tactical Wallet. This is because all wallets can hold military equipment. So even a small wallet can hold a 2x2 military tablet. Wallets can hold UAV control stations, laptops, radios, and jammers.
Wallets can also hold various large items like a jug of Hydroxide which is obviously pretty silly.
Wallets should only be able to hold money, IDs, cards, and notes. Biometric Thumb Drives are a toss-up, but I would say probably not. Maybe only in the Tactical Wallet for those.