part of the moveable lens assembly essentially however only the collimating lens and its holder 27 necessarily constitute the moveable portion of the lens assembly as the uv filter does not need to be fixed in position relative to the condensing lens reference is made to fig5 the transformation of the light beam from a collimated spot beam to a floodlight is effected by reciprocating the moveable portion of the lens assembly the condensing lens 23 and possibly the uv filter 25 as a unit to various positions in front of the light generating assembly and the fixed location fiberoptic diffusion screen 21 the position of the moveable portion of the lens assembly is changed or altered by rotating the lens barrel 27 which is engaged in the flashlight housing or container 17 via set screws 29 which are screwed through the barrel and the ends of which engage and ride in a double spiral formed in the body 27 causing the moveable portion of the lens assembly to move in and out by the rotation of the barrel 27 on the flashlight body 17 an alternative arrangement for effecting the transformation of the light beam from wide angle floodlight to narrow angle collimated or beam light utilizes a fixed position condensing lens and uv filter with a moveable lamp reflector and diffuser unit but such an assembly is more complicated and expensive to construct however the present invention contemplates both arrangements and claims such in some prior art flashlight designs the movement of the lens assembly includes a.