Did not have the presence of mind to ask Maud how many went out--but mine was sent to me in February, 2014.  I'm thinking that another owner must have installed on already.  I'd be interested in hearing from anyone in the group who received or tried one.  On the WOB, based on 10 years with my Santorin, I think that a greater factor on wear was the rusting of the spring inside the lip seal--ditto for the bowthruster.  I started paying attention to packing these using the grease designed for wheel bearings of boat trailers and had very good results.  Also, along the lines of experimentation, it would be interesting to see what would happen if all 3 lip seals were placed outward--theory vs practice.