Amazon.com : NEEWER EF-EOS M Lens Mount Adapter 0.71x Autofocus Speed Booster Compatible with Canon EF Lens to EOS M Series Camera EOS M M2 M3 M5 M6 M10 M50 M100 M200
Viltrox EF-EOS M2 EF-M Lens Adapter 0.71x Speed Booster for Canon EF lens to EOS | eBay
FD-Canon EOS M Focal Reducer Speed Booster Adapter | Pixco - Provide Professional Photographic Equipment Accessories
Amazon.com : Metabones Speed Booster XL 0.64x Adapter for Full-Frame Canon EF-Mount Lens to Select Micro Four Thirds-Mount Cameras : Electronics
Amazon.com : EF to Micro 4/3 0.71x Speed Booster, VILTROX EF-M2II EF to M43 Adapter Auto-Focus Focal Reducer Booster for GH6 GH5M2 BMPCC 4K GH4 GH5 G100 G95 G85 OM-1 EM-1 E-M1X
First Impressions: Metabones Speed Booster: Digital Photography Review
M42-Micro 4/3 Speed Booster Focal Reducer Adapter | Pixco - Provide Professional Photographic Equipment Accessories
Viltrox EF-EOS M2 Lens Adapter 0.71x Speed Booster for Canon EF Lens to EOS-M | eBay