I have used the 1GB SFP modules without issue with both the MX and MS Meraki lines. https://www.amazon.com/gp/product/B013WFH4VC/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1 I have also used Cable Matters SFP+ 10GBASE-CU Passive Direct Attached Twinax cables for connecting MS250 and MX250s without issues either. https://www.amazon.com/gp/product/B071KWNFP3/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 For $22, it can't hurt to buy a few and test it out to verify, but I don't see any issue using GTek, Cable Matters, or Humming Bird Network modules.
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