Digital Illuminated Mini Gauge / Dial 0-90psiThese are a great upgrade for the Blowtie V2, the Kegland inline Reg and the Core 360 reg. From Kegland: Traditional analogue gauges require a small capillary mechanism where a small pipe expands and unravels under pressure. This in turn drives a mechanical cog to rotate the gauge needle. This age old technique works quite well especially in large gauges but as this mechanism is manufactured smaller and smaller a tradeoff between accuracy and size