A:Answer I would bring your camera in to verify, but it appears the EF 2x ii uses an EF mount (red circle) on both ends. The SL1 can natively use it if you align the extender with the red dot on the camera. No other adapters should be needed, though it appears to only work for EF lenses. SL1 - EF 2x ii extender - EF mount lenses. The EF-M to EF and EF-S adapter associated with this post would be needed if you wanted to use the EF extender on an EF-M camera, like the M50. I have both the SL1 and the M50, the EF-M adapter on this page, and a few EF, EF-S, and EF-M lenses. I hope this helped.
