My older eyes want brighter illumination for the dash gauges. The stock bulbs with blue covers are in the jeep (1990 YJ). I removed the blue covers from some bulbs and the change was only slightly brighter and to a warmer hue. I research LED options and am happy with the results. Separately, I was curious how well the LED's would dim. They dim more than I thought they would. The stock bulbs - always run at high intensity. The LED's sometimes run less than on high. The LED's are NOT running the blue bulb cover. I could have used them - they fit - but I chose to not install them.
The included bases from this seller did not work with my instrument panel. No issue as I used the original bulb bases.
One item of note - LED's are polarity sensitive. If you put a bulb in and it does not illuminate - pull it out and reverse polarity by turning it 180 degrees in its base (or panel).