Started out with just the B2 Compute. Got hooked right away! So added Pack Cap Rear and then centers CS3 and CS5. Added Molle Cap Front so that I could create a travel bag for my luggage. Didn't like the (2) wheel hand cart offered but found a (4) wheel cart that swivels on Amazon so using this instead for the travel configuration (this would be my only suggestion - get a better cart offering). My most recent purchase was (2) Side Pocket Foxtrot's. Now I can mix and match different combinations depending on how long my travel will be. Love this versatility with the Brightline bags! Kudos for coming up with this system!