A cannula sealing apparatus includes a housing having a central axially facing aperture. A surgical instrument of 10.5 mm may seal with that aperture. Alternatively, a sealing member having an aperture that will seal with a 12 mm surgical instrument can be swung up to be aligned with the aperture. If a 10.5 mm instrument is required then a seal member can be swung up to have its seal aperture located over the central aperture. Each seal member is pivotal about a common axis.