Thank you so much for asking. We have inquired from experienced users of this product, and find that the +and - symbols are indicators for which way to turn a small screwdriver, inserted into that opening to adjust the flame length. That same opening will accept a butane recharging canister tube for recharging. Hold the canister upside down and press the tube into the torch opening. if any other users of this product have tips, please add to this discussion.