Product Discussion: AS Tool MC4 Crimper.

I do very few product reviews here on Off Grid Ham because there isn’t much that hasn’t been reviewed elsewhere a zillion times already. I also want to avoid the conflict of interest that comes from accepting free stuff in exchange for reviews. AS Tool, a small Taiwan-based operation trying to break into the US market asked me to give them a chance. I was reluctant, but they were very persuasive, so this will be one of the rare times I divert from my usual policy and actively make a recommendation.

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The MC4 tool.
As I’ve discussed in a previous Off Grid Ham article, an MC4 crimp tool is a must-have for anyone wishing to go beyond small, single solar panel systems.

Right out of the box, the first thing I noticed about the AS Tool MC4 crimper was that it was quite small. I was wondering if it was going to have the heft needed to properly crimp an MC4 connector. Looking further, the AS Tool MC4 crimper is made of heavy gauge stamped steel, finished nicely in black with plastic handles that do not easily slide off. The hinge points are large pins secured with snap rings (not cheesy rivets or machine pressed). The photo below compares the AS Tool crimper (bottom) with the one I have been using for most of my solar career.

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When I gave the AS Tool crimper a try, I was pleasantly surprised to discover that size isn’t everything. This little guy can do it. One great feature is a small spring loaded plate that holds the connector while you set up and operate the crimper. It can be tricky to get everything to line up and stay still, and this plate solves that issue.

The tool ratchet is smooth and releases without too much effort. Crimps were clean, complete and did not distort the connector.

Overall build quality and operation is very good, with one weak point: One of the tiny pins that keeps the connector holder in place fell out. I found the pin on my couch after I had put everything away. Had I not found it by accident, it would have been lost up the vacuum hose and I’d have a disabled crimp tool. Hopefully AS Tool will correct this in future versions; in the meantime I’ll fix it with a drop of super glue.

Distribution issues.
Another problem with AS Tool is not related to the quality of their products but about their distribution. One of the requirements I had before agreeing to do this review was that the item needs to be available in the USA through some reasonably easy to access sales channel. Along with the MC4 crimper, AS Tool also sent three other tools that were not included in this review due to them not being available. After all, there is no point in reviewing a product that no one can buy. I had difficulty convincing AS Tool of the wisdom of this, but after some persuasion (nagging?) they supplied this link to their eBay listings. Right now all they have listed is the MC4 tool, and that’s as an auction. I hope they will put more effort into distribution because they have some really nice stuff. They are looking for a US-based distributor, so if you have any connections, AS Tool would love to hear from you.

The AS Tool MC4 crimper is listed on eBay for $42.66 plus $24.00 shipping from Taiwan. A total of sixty-six and change, before anyone bids against you, is pushing limits (that shipping really hurts!), but it’s in line with what you’ll pay elsewhere. I’d like to see them come down on the cost of the tool or maybe offer free shipping as an offset.


  • Aside from one small, easily fixable defect, it is very well made.
  • Easy to use.
  • Spring loaded contact holder is innovative and solves an annoying problem.
  • Compact size does not sacrifice performance.


  • The “small, easily fixable defect” will disable the entire tool if not addressed.
  • Lack of distribution makes this item hard to get.
  • Shipping from Taiwan adds a lot of cost.

What you need to know.
I sincerely hope AS Tool will improve their distribution and resolve the only real quality issue the MC4 crimper has because this tool shows a lot of promise. It’s a really nice, well planned product that deserves a spot in your toolbox…if you can get your hands on one.

Off Grid Ham score: 8.0/10

$42.66 + $24.00 shipping available from eBay

Or contact AS Tool for distribution, bulk orders, and other offers.


4 thoughts on “Product Discussion: AS Tool MC4 Crimper.

  1. randall krippner

    Interesting review. Thanks for the information. I’m not dabbling in solar to the point where I need one but it’s nice to have some information on them in case I get more involved. Looks like a pretty good tool at a fair price. It’s a good illustration too of how difficult it can be for a new company to get it’s product out onto the market. I suspect a lot of small companies have the same problem. You can have one of the nicest products in the world, but trying to get a retailer or distributor to carry it is something else again.

    . I’m always surprised at how expensive crimpers are, at least the good ones. I was surprised to see this one for only $50. The one I have for Anderson PowerPole connectors was about $140, if I remember right, but it’s an amazing tool that’s easy to use and does a great job. I hate soldering coax connectors so I went with crimp on connectors for that too. That tool with the dies for various sizes of coax set me back about $200 if I remember right, but that one works beautifully too.

    Anyway, I hope they get their distribution system problems straightened out. It sounds like they have a pretty good tool at a good price.

    1. Chris Warren Post author

      Thanks for your comments, Randall. I’ve seen MC4 tools run into hundreds of dollars, but good ones can be found in the $30-$70 range. Marketing is always an issue, so I hope AS Tool finds their way. This is a worthy product.

  2. Young Lin

    Hi Chris,
    This is Young from ASTOOL Taiwan. Thanks a lot for your review on our MC4 solar crimping tool. The issue of the pin falling out has been fixed. And you are right about the distribution issue for us in the current status. In a way, it’s hard to have someone oversea to trust us and make appearance of the products in the market, especially when we are nobody and non-branded yet. We will continue to do our best to make this happen and ensure the users could have better channel to reach and buy the tool. At the same time, another 3 tools we offered are already listed in our eBay shop if you would like to take a look on it. Thank you very much to all the support.

    1. Chris Warren Post author

      Hi there! I’m glad to help even if it’s in a small way. I would think eBay would be a good sales channel until you can get more established. I wish you the best and hope things go well for you.

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