Order of development of secondary sexual characteristic in male –
In boys, the first visible sign of puberty and the hallmark of SMR 2 is testicular enlargement.
The sequence of development of secondary sexual characteristic in boys is -

Testicular enlargement —> Penis enlargement > Pubic hair growth --> Peak growth velocity —> Axillary hair —> facial hair.
Testicular development–pubic hair–axillary hair–beard
Pubic hair–testicular development–axillary hair – beard
Testicular development –beard–pubic hair–axillary hair
Axillary hair–beard –pubic hair–testicular development