We require 2 days notice and are unable to deliver at weekends. N20 will inflate 575 x 10" balloons, 400 x 11" balloons, 330x 12" balloons. You may keep the canister for 1 week, if you require it longer please telephone us on 01304 813337. Non return of the helium canister after use will result in penalty charge of £150.00 After you order online we will contact you to ask for your credit card details (as we have no access to these) as a security measure, no additional money will be taken provided the canister is returned safely.