You Do Need power plug adapter while traveling from Montenegro to Laos.

Here is Why You Need An Adapter

The outlet and plug type used in Laos are A, B, C, E and F and in Montenegro are C and F. This is how they look like.

Montenegro

In Montenegro, outlets of type C and F are in use.

Type C

Type F

Laos

In Laos, outlets of type A, B, C, E and F are in use.

Type A

Type B

Type C

Type E

Type F