For dispenser it's important to have soft control button. Because if you need to apply big force, needle may shift out of small pad. There 2 main parameters:

• Operational force
• Button form

Human skin is "soft". To be convenient, button should have big height or big square. To be sure, buttons with low operational force, available at LCSC, were tested:

The most promising are:

• Panasonic EVQQ2B03W (in left bottom corner, white button)
• ALPS Electric SKHCBKA010 (left side, blue pusher)

EVQQ2B03W looks preferable - more compact.