Straight tips are a good general purpose way to finish carbon poles and also provides a tie point for shock cord to keep poles assembled. Include a half inch per aluminum straight tip in your pole length when ordering. 
 
Tip Dia: .340" (8.6mm)
Insert Dia: .240" (6mm)
Exposed Tip Length: .5" (12.7mm)
Overall Length: 1.25" (31.8mm)