[Elecraft] SP3 vs SP4

[Geert Jan de Groot]

On 08/03/2023 04:39, elecraft-request at mailman.qth.net wrote:
> Got the SP4 for my K4D today.  So I can put the SP3 in the closet for the
> rest of my life (next to other elecraft radios and accessories) or put it
> out for sale since Elecraft no longer makes them.

What is the difference between a SP3 and a SP4? Looking at the pictures 
they seem similar apart from the text on the bezel.