The model diffuser you need is determined by the length of your lens and the height of your flash.

Pick a model by its name as follows:

1. All model names start with “KR”, my initials.
2. Measure your lens length from the mount to the end of the lens to compare sizes.
   1. Focal length for Olympus macro lenses:
      • 30 for the 30mm macro, which is 60mm long in total;
      • 60 for the 60mm macro, 70mm in total;
      • 90 for the 90mm macro, 113.5mm in total.
3. Measure your flash unit from the hotshoe to the top in the folded down position to compare.
   1. Code for the flash model:
      • O = Olympus FL-LM3:
      • G = Godox V350, Godox TT-350, or similar sized flashes like the Olympus FL-600R, height above the hot shoe approximately 11 cm.
      • GV = Godox V480, or similar sized flashes like the Olympus FL-700WR; height approximately 12.5 cm.
      • GX = Godox V860III or similar sized flashes like the Olympus FL-900R Height / approximately 13.5 cm.
      • iT = Godox iT32, height 9cm, or
      • No code = Meike MK320 height 6 cm.

Examples:

• KR-60 is for a 60mm macro size lens with a Meike MK-320 flash;
• KR-90GV is for the 90mm macro sized lens and Godox V480;
• KR-90GX is for the 90mm macro sized lens with the Godox V860III.

Special cases that don’t fit the normal pattern:

• KR-TM is for the Olympus 300mm f/4 IS Pro and the OM 50-200mm f/2.8 IS Pro lenses and the Godox V860II or V1 Pro flash units.

When you place your order, select:

• The colour;
• The filter thread diameter for your lens;
• Other options such as the Raynox Package (for the 30 & 60mm lens only);
• Decide whether you want a Standard or a Mini sized diffuser where available.

This video demonstrates the new mini range:

This video demonstrates the diffuser installation step-by-step:

I go through flash settings in detail in this video:

You can find those on my FaceBook page.

You can see examples in my Flikr album, as well as my gallery.