This is a World War II Bermuda Censor cover from 1942.  It has the I.B./6044 censor tape, but the "I.B." has been crossed out and "I.C." has been written in Ink underneath it.

British Censors were assigned a number which they kept when they moved from station to station.  In this case, that was 6044.

This item is over $100 USD so I will ship it using Priority Mail in the United States, and Registered Mail Overseas at buyer's expense.  This is to ensure that it reaches you in a safe and timely manner, and includes tracking!