Stickiness is a hidden variable for all mods which is the probability of a mod not being destroyed when struck by critical hits from XMPs or Ultra Strikes. Common Shields and all other mods (link amps, hacking mods etc) have 0 stickiness regardless of their rarity (excluding turrets, these have a 20% stickiness. Force amps do not possess this). This means that these mods will be destroyed whenever an agent delivers critical hits with XMPs or ultra strikes. Intuitively, this probability increases with rarity of the shield.

See also: Portal Shield#Mitigation and Stickiness