Boost gauges can be a lot more than that. Electronic gauges (not digital, like Autometer and such) get pricey because they’re a bit more accurate since you’re not running a vacuum line from under the hood to the back of the gauge. With electronic gauges, you only run a line for a few inches, and then you connect it to a sensor, which runs (through wires) to the back of the gauge. No pressure loss, really. Reliability, consistency, and accuracy > *