SMO or OP reflector. The difference is shown below
Please be careful when changing reflectors, you don't want to scrape against the emitters. The recommended procedure is:
---loose the lens ring
---place the LED head on a flat surface
---take away the housing (with the emitter inside), the reflector is now on the top of the glass lens
---replace with a different reflector
---put back the housing
---flip over the LED head and tight the lens ring.
