A new mechanic that has been introduced to Monster Hunter Generations Ultimate is SP (Style Power-up) and when equipped to a Hunter Art and activated will enable you and any party members that are nearby to enter into SP mode. How this mode will effect each player will depend on which Hunting Style they are using. Below is a list of the Hunting Styles and how SP will effect them.
Guild Hunter Style
You get faster item use.
Striker Hunter Style
Your Hunter Art gauge will slowly fill up on its own.
Aerial Hunter Style
Your stamina will start recovering as soon as you vault off a monster.
Adept Hunter Style
The window for Adept Evading/Guarding is increased.
Valor Hunter Style
Your Valor gauge fills faster.
Alchemy Hunter Style
Your alchemy gauge fills up faster (Alchemy also has access to SP levels 2-4, which give faster stamina recovery, health regeneration and makes monsters easier to flinch).
Prowler
Your support moves will use up less gauge and become easier to execute.