Its these: (Yes, i absolutely adore cute things! :D) http://www.amazon.com/Kotobuki-Condiment-Containers-Animal-Friends/dp/B00DVEGAWE/ref=sr_1_2?ie=UTF8&qid=1388987527&sr=8-2&keywords=bento+container

It isnt a problem with them opening its more of a problem with fitting them into the bento. If i put them in the bag that i carry it in then they end up getting too jostled and end up spilling and i end up with gorgonzola all in my bag! Ill be sure to try the saran wrap idea! or just find a pencil bag or something else that i can leave in my backpack without getting cheese all over my notes..