TravelSim offers a dual-profile SIM card solution that provides a seamless roaming experience. The SIM card contains two separate profiles - a local profile for domestic use and a TravelSim profile that automatically activates for cheaper rates when roaming internationally. TravelSim handles the technical implementation and profile switching, while sharing 35% of airtime revenue with partners to cover operational costs. Partners need to purchase a minimum of 10,000 dual-profile SIM cards at $4.20 each and provide an initial $10,000 deposit for future airtime.