Check the listing for details. Spark Plug Gap Gauges ‘Silver Dollar’ Taper Gauge & Wire Gauges, Select: Type. Condition: New. Listed at 2.99 USD. Spark Plug Gap Gauges ‘Silver Dollar’ Taper Gauge & Wire Gauges, Select: Type Purchase is for one spark plug gap gauge. Accurately measure and adjust spark plug gaps. Circular ‘Silver Dollar’ gauge description: Show inch and metric sizes on the fronts and backs of the gauges, respectively.Circular taper gap gauge shows inch and millimeter ranging from .020" to 0.100" (0.6 - 2.4mm)Features a beveled round hole for opening electrode gaps. Can use the hole to hang the gauge on your key ring.Shows inch measurements ranging from 0.020" to 0.100" on one side and 6 mm to 2.4 mm on the other side.Size: 1.5" x 1/8" Chrome Plated Steel Champion Spark Plug Circular Taper Gap Gauge CT481 MPN: CT481UPC: 037551916719 OEM Spark Plug Circular Taper Gap Gauge 25352MPN: 25352UPC: 076812253521 HyperTough Spark Plug Circular Taper Gap Gauge 4706MPN: 4706UPC: 820909047063 CTA 9 Wire Medium Gap Gauge 3238Nine wire gap gauge shows inch on front and millimeters on back as follows:Inch Metric (mm)0.025 0.6350.030 0.7620.035 0.8890.040 1.0160.044 1.1180.045 1.1400.050 1.2700.055 1.4000.060 1.524Features 2 keys for opening/closing electrode gaps. Size: 2.2" x 3/16" Flat Steel FinishMPN: 3238UPC: 053001032389 GearWrench Spark Plug 6 Wire Regular Gap Gauge 166DSix wire gap gauge shows inch on front and millimeters on back as follows:Inch Metric (mm)0.025 0.6350.030 0.7620.034 0.8640.035 0.8890.040 1.0160.045 1.143Features 4 keys for opening/closing electrode gaps. Size: 2.5" x 3/16" Flat Steel FinishMPN: 166D / 2ZPF9UPC: 082171001666 Lesle Spark Plug 6 Wire Wide Gap Gauge 67900Six wire gap gauge shows inch on front and millimeters on back as follows:Inch Metric (mm)0.040 1.0160.044 1.1180.045 1.1400.050 1.2700.060 1.5240.080 2.030Features 4 keys for opening/closing electrode gaps. Size: 2.2" x 3/16" Flat Steel FinishMPN: 67900UPC: 083045679004 OEM Spark Plug 6 Wire Wide Gap Gauge 25026Six wire gap gauge shows inch on front and millimeters on back as follows:Inch Metric (mm)0.040 1.0160.044 1.1180.045 1.1400.050 1.2700.060 1.5240.080 2.032Features 4 keys for opening/closing electrode gaps. Size: 2.2" x 3/16" Flat Steel FinishMPN: 25026UPC: 076812250261 OEM Spark Plug 6 Wire Regular Gap Gauge 25226Six wire gap gauge shows inch on front and millimeters on back as follows:Inch Metric (mm)0.025 0.6400.030 0.7600.034 0.8600.035 0.8900.040 1.0200.045 1.140Features 4 keys for opening/closing electrode gaps. Size: 2 1/8" x 3/16" Flat Steel FinishMPN: 25226UPC: 076812252265 USA domestic shipments are shipped USPS First Class Mail with Tracking International shipments are shipped USPS First Class International Mail with Tracking Review: 5 Stars: The Champion ‘Silver Dollar’ taper gauges last a long time (I still have my original one from 20 years ago on my key ring and use it daily), so it is an excellent value for the price, and the techs love that they have a handy gap gauge right in their pocket instead of having to dig out a gap gauge from their toolboxes. Note that the ‘silver Dollar’ gap gauges are best for use on new spark plugs. if you are working with worn plugs, use a wire gauge.