In the "TEU-FEL" project of the University of Twenty, The Netherlands, an FEL will be built which consists of a photocathode linac which will accelerate the electrons up to 6 MeV, a race-track microtron which will accelerate the electrons up to 25 MeV, a hybrid undulator, an electron bending system, and an optical cavity . The project will be carried out in two phases. In phase I an FEL will be built with the photocathode linac and the hybrid undulator only. No optical cavity will be used: the electrons will be focussed directly into the undulator so that the FEL will work as an amplifier of spontaneous emission or, eventually, as an amplifier of an injected signal . In phase II the race-track microtron will be used and the undulator will be placed inside an optical cavity and then, of course, an electron bending system will be required . The main characteristics of the project are summarized in table 1 . In the remaining part of the paper we will describe in some detail the instrumental parts of our FEL.