What's the difference between a Splinter Cell and a D.I.C.K?

Thank you for all your postcards and, as someone pointed out,  I must add an "S" to D.I.C.K.

Well spotted!

...and they keep coming! Thanks again for all the postcards. We now have 10 D.I.C.K.s  and we are closing in on the Splinter Cell.