The gray Insert for the Chobe 19-24L Shoulder Bag from Gura Gear is custom fit for the bag. It's padded, removable and made from a 210D high-density nylon. The insert contains five padded touch fastened dividers that can be configured to accommodate whatever gear you need. It's large enough to hold your 300mm f/2.8 lens but can also be customized to hold two DSLRs and up to 3-4 smaller lenses or your flash. Both the insert and dividers have touch fastened attachment points on the interior.