Abstract: An extendable stirrup attachable to a conventional stirrup strap of a conventional saddle that has a free end and a throughbore disposed in proximity to the free end of the conventional stirrup strap of the conventional saddle that includes a locking device assembly, a rack assembly, and stirrup assembly. The locking device assembly is attachable to the conventional stirrup strap of the conventional saddle. The rack assembly has a lower end and is lockingly extendable from, and lockingly retractable in, the locking device assembly. And, the stirrup assembly is pivotally mounted to the lower end of the rack assembly, so that the stirrup assembly can be lowered and raised to adjust for different height equestrians.

Abstract: A microfocus X-ray tube having an improved cathode assembly including a filament mounting disk for adjustably mounting a flat ribbon filament or a round wire filament such that the filament extends through an aperture in a focal plane disk which provides a uniform focusing field to the filament as well as a uniform heat sink surface.