This replacement eye piece offers comfort for your viewfinder. The EF type is the standard eye cup for most of the newer models of Canon EOS range from about the 400D upwards. The EF type cup will fit most models, however for cameras with singe digigits (eg. the 5D), or old film cameras, it is best to go for the EB type which has a wider rubber part. 
 
This item is used - but has been checked and is in perfect condition.