Only while insubstantial

http://www.sjgames.com/gurps/faq/FAQ4-5.html#SS5.3.2

5.3.2. Do I need Affects Substantial enhancement, if my Innate Attack/Magic only works while I'm insubstantial?

If it affects the material world, then you need Affect Substantial. If it only affects the insubstantial world, then you do not. The 'Only while insubstantial' by itself is usually worth -10%.

See also

• Alternate Form
• Alternative Abilities
• Only in altered body form
• Only When Insubstantial