This item is used on multiple models in different quantities.
To replace the click tongue and button on models where it is peened into place, use a dremel drill with a fine tip to remove the old click tongue and click button. Then peen the new ones into place. Peening is when you gently tap the end of the click button with a small hammer until the metal spreads out enough to hold the click tongue in place.
The neck on this button, where it sits in the plate, measures approx. 5.08 mm or .200 inch
NOTES FOR DIFFERENT MODELS AND CHANGES:
150:Measure the necks! On older 150 reels a 36-60CH may be required. It measures .248 (roughly 1/4 inch) from just under the cap to the edge of the dropdown, at the "neck".