The paper presents various designs of several medium and small size Dense Plasma Focus (DPF) chambers intended for numerous applications, a description of technologies used in these facilities, and some results reached with these devices by using a number of diagnostic techniques. In present experiments the DP foci have been used mainly as an X-ray source. We discuss here how it is possible to satisfy absolutely new and very strict demands on the construction and technology for the devices to be eventually applied in science and industry. Between these characteristics there are a high repetition rate (typically 1...15 Hz) and a long lifetime (over 1 milion shots). Their switching elements, a collector and chambers must withstand a high quasi-continuous heat load (up to 100 kW). High energy density in the central part of the chamber anode and the necessity to provide a channel for radiation extraction demanded a special construction and specific materials implementation in this region. Their X-ray spectrum should be tuned. They have to operate with different working gases and preferably in a wide range of pressures. All these points are discussed in this report. Capabilities of the described techniques are illustrated by results of the recent experimental studies carried out with facilities located at the Nanyang Technological University (NX1) as well as at the Lebedev Physical Institute (PF-0.2).