Garmin GPSMAP 238

[Ramjam]

I have just come across a Garmin 238 but it has no brackets for it. I have found a swivel mount on the net, but not to sure if it is the right one. The manual for the sounder has the title 188/238 Sounder, does this mean they would be the same physical size. The swivel mount states it is suited for a 188 sounder and I don't have any feedback from the supplier yet.
Any help, part numbers ect. would be appreciated.
Thanks.