While at a friends house over the weekend - he commented - your front tires look low - nah said I - just checked them - got out my ancient gauge - stick with plastic bit that is pushed out the end- 29# it sez - yep low it is I said. He whipped out a digital gauge and said check it with this - 24# it sez. Being off 5# is way too much. I suppose the round dial gauges are better but this thing seems to be very accurate - bought one and got the identical readings 31.5 as on my friends digital gauge. This one is called Monkey Grip - has a permanent but replaceable batteries and is less than . Not affiliated with any auto parts products at all but have ruined some tires by running them under inflated.