ST-Based

ST-Based is short for Melee Attack (ST-Based) which is an enhancement introduced on page 103 of GURPS Powers
P154 clarifies something:
*For a melee attack, all choices are valid except All-Out Attack (Strong) – only attacks with the Melee Attack (ST-Based) enhancement (p. 103) have that option.
==See also==
*Enhanced ST-Based Attacks
*Modifying ST-Based Damage
Category:Enhancements