Gift for Coworker who covered my job while I was on Maternity leave?

Erica

3 months before I left for maternity leave I started a new job at a wonderful company. They have been more than happy to let me take my full 12 weeks needed and my coworkers have taken over my responsibilities with no questions asked. I know my responsilities have not been easy since I personally manage 5 employees and they have their group to manage as well. I was thinking of getting the two employees a gift for helping me out while I was out. What would be an appropriate gift? I'm planning on taking them to lunch before I go back to get caught up on some of the things that have changed in the last 12 weeks. I just feel like I owe them more since they are not being compensated for their extra workload. Any ideas on gifts would be appreciated!