BTW, Harbor Freight has 4” calipers on sale for $10 until next week. 6” are $20 until the end of the month.
I was in my HF Saturday, and the 4” was $8, advertised price, no coupon. I have a coupon for the 6” at $9.99. I didn’t buy the 4” because I already have the 6”. I was so proud of myself!
I have exactly the same, the battery holder was not so tight so I put a piece of paper in it. Before I’ve done this it sometimes reseted itself. Exactly with two batteries one in a blister…
I bought it from a cheapo electronic retailer for 10€=13$.
The small opening on the side is a serial connection, some guys on the net use this for a external display on a lathe or so. There are more expensive calipers available which have there a mini USB plug, on our model there’s just a hole with the circuit traces.
You can also find these calipers made of non-conductive plastic. They usually have a resolution of around 0.01” and are not very good for things like scribing lines and removing pills and tail switches.
https://ssl.zoovy.com/c=IZLt5Y9VP11l9bfZviOnG9b2o/s=www.toolprice.com/product/2962/Digital-Caliper-6—Vernier-Caliper—LCD—Stainless-Steel—SAE—Metric—MM.html (sent by Yahoo! Toolbar)
Just bought this one today…Free shipping and in U.S.
I have 6 of these calipers 2 from harborfreight 3 from ebay and one that was sold in advanced auto under the ampro brand. Hold up pretty well and are accurate enough for non crucial measurements. I have had the ampro for at least 7 years.
They do seem to loose zero quite often. If the display starts to have a slow reaction time when you move the calipers its time to replace the batteries. I had one caliper while I was turning a heatsink for a Maglite do this and ever time I took a few thousandths off approaching the finally pass, the caliper said I needed a few more thousandths off. After doing this twice I new something was wrong so I measured with a different set of calipers and I had already over shot the run way, had to start all over again. If the batteries get low they can give you a false reading.
When the caliper is off (no matter if you turn it off or its a automatic off) the caliper is still draining your batteries. You can test this by turning the caliper off and then moving the caliper about a inch or so. Now turn the caliper back on, if the caliper reads about a inch then it was reading the movement while it was off the display was just off as already mentioned. The best way to save battery life is to remove them when not in use.
I spent several years using this type caliper and they are a decent caliper for the money. You can take them apart and do a little polishing with 1000 grit sand paper on the contact parts for a smother action. Really helps if the movement seems kind of rough or sticky. You can also use mothers mag wheel polish to help smooth out the rule part of the caliper that the display rides on.
I finally broke down and purchased a Mitutoyo absolute caliper. The difference is worth ever penny to me. But not ever one needs this type of caliper. If you ever need to purchase a Mututoyo caliper, there is a guy on ebay that sells these constantly brand new in the box. They usually sell from $75 to $100. I purchased my first one for $88.15 shipped. The second one I got for 78.15 shipped. It took weeks to finally get a deal on these. This is the link to his store, he has two for auction now.
Not everyone needs this type caliper which I understand. Just thought I tell others that might be in the market looking for a good deal on a Mit. 
Just yesterday local store for “stuff” informed, that they have very similar ones for sale at 10EUR.
Thanks for the review!!
I wonder what’s the best online deal for these things. I think lowest I saw was ~$13 on Ebay or Aliexpress (SS with case).
£4.95 free delivery Cheapest I could find on ebay but it says it’s plastic. Might be good for checking battery lengths. It’s located in U.K. so no waiting on a Chinese delivery.
This is the same or similar to one I bought last year for £6.25. Now £9.99
They do fluctuate in price, so it’s worth watching for a while, Amazon has none cheaper at the moment.