LED lights built in to the Ender 3 S1 Pro (and add-on for the regular S1) were making hot spots on the bed when shooting time-lapse and so need a bigger diffuser to soften the light. This diffuser is half the length of the light bar so you will need to print 2 of them. Printed with clear filament using 3 walls of .8mm with a .4 nozzle. Polymaker PETG Clear filament worked great at 235/70c.