A point to note. The flash unit is described as AUTO ZOOM but as far as I can tell there is no Auto Zoom Facility. Why they described it as such is a mystery to me?.

 

Sunpak Autozoom 3600 Specifications: English
Guide Numbers:With ASA 100 film 36 (in meters) 120 (in feet).
With ASA 50 film 25 (in meter) 85 (in feet) BCPS: 2550 With AA Nicad Batteries (6): Maximum Power Minimum Power.
Number of flashes per set 50 430 Recycling Time 4 sec. 0.3sec.
With AA Alkaline Batteries (61: Number of flashes per set 100 800 Rerycling Time 8 sec. 0.3 sec. 
Automatic Distance Range 0.5m-12.8m 11.6'-42'l at maximum aperture 0.5m-4.5m {1.6'-15'} at minimum aperture. Flash Duration; 1/850th -1/2000th second.
Sensor Acceptance Angle: 15"
Angle of illumination: Horizontal 50o x Vertical 45o 35mm lens on 35mm camera (Vertical Position) 50mm lens on 35mm camera (Horizontal Position).
Color Temperature: 5500" Kelvin.
Dimensions : 248 x 1O1 x 101mm/9.7" x 3.9" x 3.9"