  In this paper, the development of the dual mirror Small Size Telescopes (SST)
for the Cherenkov Telescope Array (CTA) is reviewed. Up to 70 SST, with a
primary mirror diameter of 4 m, will be produced and installed at the CTA
southern site. These will allow investigation of the gamma-ray sky at the
highest energies accessible to CTA, in the range from about 1 TeV to 300 TeV.
The telescope presented in this contribution is characterized by two major
innovations: the use of a dual mirror Schwarzschild-Couder configuration and of
an innovative camera using as sensors either multi-anode photomultipliers
(MAPM) or silicon photomultipliers (SiPM). The reduced plate-scale of the
telescope, achieved with the dual-mirror optics, allows the camera to be
compact (40 cm in diameter), and low-cost. The camera, which has about 2000
pixels of size 6x6 mm^2, covers a field of view of 10{\deg}. The dual mirror
telescopes and their cameras are being developed by three consortia, ASTRI
(Astrofisica con Specchi a Tecnologia Replicante Italiana, Italy/INAF), GATE
(Gamma-ray Telescope Elements, France/Paris Observ.) and CHEC (Compact High
Energy Camera, universities in UK, US and Japan) which are merging their
efforts in order to finalize an end-to-end design that will be constructed for
CTA. A number of prototype structures and cameras are being developed in order
to investigate various alternative designs. In this contribution, these designs
are presented, along with the technological solutions under study.

Instrumentation and Methods for Astrophysics;High Energy Astrophysical Phenomena;High Energy Physics - Experiment;Instrumentation and Detectors