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. Each seal member has a surface that faces a housing such that both parts can seal at their facing surfaces when either of the seal members are swung up into the position where the opening is over the central opening.