Fixed Or Variable Slits (bandwidths) ● For Stand-alone Models, All Software Methods Are Included As Built-in Standard; This Eliminates The Need Of Software. ● Online Software Upgrade Via Internet Helps To Keep It Updated. ● Data Download-to-PC Software Expands The Data Storage To Unlimited. ● The Stand-alone Models Has 5 Inch Screen And The PC Models Has UVNis Analyst Software.