Miniature potentiometers often look like this
http://www.futurlec.com/Pictures/POTTRIM-VERT.jpg
or this
http://rocky.digikey.com/weblib/CTS/Web%20photos/U262R%20SERIES%20WHITE.jpg
and the posh one like this
http://www.solarbotics.com/assets/images/rt20k/rt20k_pl.jpg
Usually adjusted with a small nylon trim tool - a tiny screwdriver will often do as well
Peccavi, June 2009