Marine How To says
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NOTE:When choosing crimp terminals I would urge you to buy from companies with a reputation to uphold and a long history for quality. If you buy from companies such as AMP/Tyco, Molex, FTZ, Burndy, Thomas & Betts (T&B), *3M, Ancor etc. and you will get better quality terminals than the cheap no-name junk that has infiltrated the country over the last 20 years or so."
Marine Wire Termination - Tools of the Trade MHT Recommended Tools: The products below are our top picks for crimp tools. RecommendationsI include; PRO GRADE, MARINE GRADE, & PENNY SAVER GRADE. Every tool recommended BELOW, we have tested here.
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But I have used the cheap ones with no apparent failings. The cheap ones seem to use thinner metal and maybe the strength is less, but I never rely on the crimp for strain. Definitely look for tinned solid copper.