I used the red connectors. Spliced a 22 AWG wire and a 18 AWG wire. The 22 gauge was marine wire, the 18 gauge was low voltage 12V O2 free stranded wire. Crimp was satisfactory, but the heat shrink would not seal properly on the 22 gauge wire. The 18 gauge was tolerable. Used a commercial heat gun. Used my own heat shrink to ensure a waterproof connection. Not a bad product, but not a superior product. Was worth what I paid for. On!y bought a small pack, so if the rest don't work, no big deal. It is a wait and see if I reorder this again.