SUSAT - Sight Unit Small Arms Trilux
Derived from the Trilux sight used on the SLRs. This optical unit can be found mounted on the SA-80 rifle and LSW, though it has been seen mounted on other support weapons of late. It provides a 4x optical magnification.
Problems with the SUSAT include the mount easily losing zero when dropped, since it is not as securely attached to the receiver of the weapon as it could be. The adjustments are tricky, coarse and external (very old school), and the eye relief is extremely short. The SUSAT tube itself, however, is extremely robust.