We have love for the GC300! and the infamous Toyota Aristo! There are not enough spots for gauges in the JZS chassis. This allows you to have gauges in plain view sight of the factory gauge cluster with no obstruction of vital information you're used to seeing on a daily basis.
The gauge pods naturally come in 52mm or 60mm (the 60mm version is available in a different product listing) diameter. They will fit ANY depth gauge.
They are also available in an uncapped or capped version. The Capped version does obviously have a depth limit but we have tested the oldest HKS, Blitz and Sard gauges from way back in the day when Zach Morris had a cell phone and they all fit just fine. Capped gauge pods do have a small slit out the back to route your wiring in a nicely tucked and responsible manner.
Just like all of our steering wheel gauge pods. You can mount this one of two ways. Either you utilize the included hardware and drill two very tiny 3mm holes for each gauge pod OR lay down double-sided tape for a semi-permanent solution.