Charger Tip  M7 19V(90W Max) 5.5.x 2.1mm for ACER - LITEON - NEC 

Specifications:

19V(90W Max)
5.5x2.1mm

ACER:

19V/3.16A
19V/3.42A
19V/4.74A

LITEON:

19V/3.16A
19V/3.42A

NEC:

19V/3.16A etc

Suitable Charger models:
PT-31
PT-90W-U11
PT-120
PT-120WATT
PT-80WATT