I have a used Olympus T-32 flash for the OM series of SLR cameras. It is in excellent condition and works great. Requires 4 AA batteries, not included. Full manual and automatic by sliding out back panel. It will ship without AA batteries.
Read all about it here:
http://mir.com.my/rb/photography/hardwares/classics/olympusom1n2/shared/flash/t32flash/index.htm