Possible Clues:

• Are shortly to be found in Seven Up to make one jumpy
• They give one the feeling that that's one R in seven
• Impulse transmitters
• They give one the feel of the Severn
• Ever get the feeling of being from pole to pole?
• Never wrong going to school with butterflies
• Cause of belly butterflies
• Reason of shaking hands?
• of steel (steady courage)
• Uneasy psychological state