Material Chrome Plastic or Chrome Plated Steel Installation Snap-on Unit & Package Sold by each, carded for display Steel w/o Visor Chrome Plastic Chrome Plated w/o Visor w/Visor Make Gauge Type Size 68164 — 68395 Ferightliner Small gauge 2-1/4″ dia. — 68220 68393 (ridged w/thin visor) Freightliner/Peterbilt Pyrometer 3-5/16″ dia. — — 68398 (plain w/thick visor) Freightliner/Peterbilt Pyrometer 3-3/4″ dia. 68172 68222 68224 (plain w/thick visor) Freightliner/Peterbilt Speed/Tachometer 3-5/8″ dia. — — 68394 (ridged w/thin visor) Freightliner/Peterbilt Speed/Tachometer 3-3/4″ dia. — — 68397 Freightliner Century — 4″ I. D. 4-7/8″ O.D.