Such a false sense of confidence for a product[1] whose actual performance specs aren't properly published. And it isn't just Longacre playing this game.
If you're in the recreational motorsports scene, you've probably noticed what I'm referring to. If you're an engineer in the same, it probably has driven you nuts. I'm not even talking about full NIST traceability (although if a serious customer wants that and is willing to pay, it shouldn't be an issue...good luck with that) but just a really basic warm and fuzzy.
Intercomp[2] pulls the "Certified Accuracy" bullshit marketing wank, but doesn't even specify the overarching standard that their products are certified against.
Joes Racing[3] labels their analog "Pro" model as "ANSI grade B40.1", but if you've actually read ASME B40.1 proper (currently published in ASME B40.100-2005, which contains 5 related standards including B40.7 for digital gauges), you'd know that's bullshit marketing wank...for all anyone knows, they're selling pseudo-Grade D chinesium trash at a premium price point.
Pick any consumer-grade product and you'll discover the same pattern.
The only markets I've seen any semblance of meaningful published specifications with respect to pressure gauges are industrial and scientific/metrology. Of course, the typical players in those markets aren't nearly as naive.
[1] http://www.longacreracing.com/products.aspx?itemid=1716&prod...
[2] https://www.intercompracing.com/documents/Literature/7005110...
[3] https://www.joesracing.com/product/joes-pro-tire-gauges/